Dusk was already falling when the 9 p.m. Continental boat-train pulled out of Charing Cross, with Seymour Merriman in the corner of a first-class compartment. It had been a glorious day of clear atmosphere and brilliant sunshine, and there was every prospect of a spell of good weather. Now, as the train rumbled over the bridge at the end of the station, sky and river presented a gorgeous color scheme of crimson and pink and gold, shading off through violet and gray to nearly black. Through the latticing of the girders the great buildings on the northern bank showed up for a moment against the light beyond, dark and somber masses with nicked and serrated tops, then, the river crossed, nearer buildings intervened to cut off the view, and the train plunged into the maze and wilderness of South London.

The little pleasurable excitement which Merriman had experienced when first the trip had been suggested had not waned as the novelty of the idea passed. Not since he was a boy at school had he looked forward so keenly to holidays. The launch, for one thing, would be a new experience. He had never been on any kind of cruise. The nearest approach had been a couple of days' yachting on the Norfolk Broads, but he had found that monotonous and boring, and had been glad when it was over. But this, he expected, would be different. He delighted in poking about abroad, not in the great cosmopolitan hotels, which after all are very much the same all the world over, but where he came in contact with actual foreign life. And how better could a country be seen than by slowly motoring through its waterways? Merriman was well pleased with the prospect.

And then there would be Hilliard. Merriman had always enjoyed his company, and he felt he would be an ideal companion on a tour. It was true Hilliard had got a bee in his bonnet about this lorry affair. Merriman was mildly interested in the thing, but he would never have dreamed of going back to the sawmill to investigate. But Hilliard seemed quite excited about it. His attitude, no doubt, might be partly explained by his love of puzzles and mysteries. Perhaps also he half believed in his absurd SUGGESTION about the smuggling, or at least felt that if it were true there was the chance of his making some coup which would also make his name. How a man's occupation colors his mind! thought Merriman. Here was Hilliard, and because he was in the Customs his ideas ran to Customs operations, and when he came across anything he did not understand he at once suggested smuggling. If he had been a soldier he would have guessed gun-running, and if a politician, a means of bringing anarchist literature into the country. Well, he had not seen Madeleine Coburn! He would soon drop so absurd a notion when he had met her. The idea of her being party to such a thing was too ridiculous even to be annoying.

However, Hilliard insisted on going to the mill, and he, Merriman, could then pay that call on the Coburns. It would not be polite to be in the neighborhood and not do so. And it would be impossible to call without asking Miss Coburn to come on the river. As the train rumbled on through the rapidly darkening country Merriman began once again to picture the details of that excursion. No doubt they could have tea on board.... He mustn't forget to buy some decent cakes in Bordeaux.... Perhaps she would help him to get it ready while Hilliard steered and pottered over his old engines.... He could just imagine her bending over a tea tray, her graceful figure, the little brown tendrils of her hair at the edge of her tam-o'-shanter, her brown eyes flashing up to meet his own....

Dover came unexpectedly soon and Merriman had to postpone the further consideration of his plans until he had gone on board the boat and settled down in a corner of the smoker room. There, however, he fell asleep, not awaking until roused by the bustle of the arrival in Calais.

He reached Paris just before six and drove to the Gare d'-Orsay, where he had time for a bath and breakfast before catching the 7.50 a.m. express for Bordeaux. Again it was a perfect day, and as the hours passed and they ran steadily southward through the pleasing but monotonous central plain of France, the heat grew more and more oppressive. Poitiers was hot, Angouleme an oven, and Merriman was not sorry when at a quarter to five they came in sight of the Garonne at the outskirts of Bordeaux and a few moments later pulled up in the Bastide Station.

Hilliard was waiting at the platform barrier.

“Hallo, old man,” he cried. “Jolly to see you. Give me one of your handbags. I've got a taxi outside.”

Merriman handed over the smaller of the two small suitcases he carried, having, in deference to Hilliard's warnings, left behind most of the things he wanted to bring. They found the taxi and drove out at once across the great stone bridge leading from the Bastide Station and suburb on the east bank to the main city on the west. In front of them lay the huge concave sweep of quays fronting the Garonne, here a river of over a quarter of a mile in width, with behind the massed buildings of the town, out of which here and there rose church spires and, farther down-stream, the three imposing columns of the Place des Quinconces.

“Some river, this,” Merriman said, looking up and down the great sweep of water.

“Rather. I have the Swallow 'longside a private wharf farther up-stream. Rather tumble-down old shanty, but it's easier than mooring in the stream and rowing out. We'll go and leave your things aboard, and then we can come up town again and get some dinner.”

“Right-o,” Merriman agreed.

Having crossed the bridge they turned to the left, upstream, and ran along the quays towards the south. After passing the railway bridge the taxi swung down towards the water's edge, stopping at a somewhat decrepit enclosure, over the gate of which was the legend “Andre Leblanc, Location de Canots.” Hilliard jumped out, paid the taxi man, and, followed by Merriman, entered the enclosure.

It was a small place, with a wooden quay along the river frontage and a shed at the opposite side. Between the two lay a number of boats. Trade appeared to be bad, for there was no life about the place and everything was dirty and decaying.

“There she is,” Hilliard cried, with a ring of pride in his voice. “Isn't she a beauty?”

The Swallow was tied up alongside the wharf, her bow upstream, and lay tugging at her mooring ropes in the swift run of the ebb tide. Merriman's first glance at her was one of disappointment. He had pictured a graceful craft of well-polished wood, with white deck planks, shining brasswork and cushioned seats. Instead he saw a square-built, clumsy-looking boat, painted, where the paint was not worn off, a sickly greenish white, and giving a general impression of dirt and want of attention. She was flush-decked, and sat high in the water, with a freeboard of nearly five feet. A little forward of amidships was a small deck cabin containing a brass wheel and binnacle. Aft of the cabin, in the middle of the open space of the deck, was a skylight, the top of which formed two short seats placed back to back. Forward rose a stumpy mast carrying a lantern cage near the top, and still farther forward, almost in the bows, lay an unexpectedly massive anchor, housed in grids, with behind it a small hand winch for pulling in the chain.

“We had a bit of a blow coming round the Coubre into the river,” Hilliard went on enthusiastically, “and I tell you she didn't ship a pint. The cabin bone dry, and green water coming over her all the time.”

Merriman could believe it. Though his temporary home was not beautiful, he could see that she was strong; in fact, she was massive. But he thanked his stars he had not assisted in the test. He shuddered at the very idea, thinking gratefully that to reach Bordeaux the Paris-Orleans Railway was good enough for him.

But, realizing it was expected of him, he began praising the boat, until the unsuspecting Hilliard believed him as enthusiastic as himself.

“Yes, she's all of that,” he agreed. “Come aboard and see the cabin.”

They descended a flight of steps let into the front of the wharf, wet, slippery, ooze-covered steps left bare by the receding tide, and stepping over the side entered the tiny deckhouse.

“This is the chart-house, shelter, and companion-way all in one,” Hilliard explained. “All the engine controls come up here, and I can reach them with my left hand while steering with my right.” He demonstrated as he spoke, and Merriman could not but agree that the arrangements were wonderfully compact and efficient.

“Come below now,” went on the proud owner, disappearing down a steep flight of steps against one wall of the house.

The hull was divided into three compartments; amidships the engine room with its twin engines, forward a store containing among other things a collapsible boat, and aft a cabin with lockers on each side, a folding table between them, and a marble-topped cupboard on which was a Primus stove.

The woodwork was painted the same greenish white as the outside, but it was soiled and dingy, and the whole place looked dirty and untidy. There was a smell of various oils, paraffin predominating.

“You take the port locker,” Hilliard explained. “You see, the top of it lifts and you can stow your things in it. When there are only two of us we sleep on the lockers. You'll find a sheet and blankets inside. There's a board underneath that turns up to keep you in if she's rolling; not that we shall want it until we get to the Mediterranean. I'm afraid,” he went on, answering Merriman's unspoken thought, “the place is not very tidy. I hadn't time to do much squaring—I'll tell you about that later. I suppose”—reluctantly—“we had better turn to and clean up a bit before we go to bed. But”—brightening up again—“not now. Let's go up town and get some dinner as soon as you are ready.”

He fussed about, explaining with the loving and painstaking minuteness of the designer as well as the owner, the various contraptions the boat contained, and when he had finished, Merriman felt that, could he but remember his instructions, there were few situations with which he could not cope or by which he could be taken unawares.

A few minutes later the two friends climbed once more up the slippery steps, and, strolling slowly up the town, entered one of the large restaurants in the Place de la Comedie.

Since Merriman's arrival Hilliard had talked vivaciously, and his thin, hawk-like face had seemed even more eager than the wine merchant had ever before seen it. At first the latter had put it down to the natural interest of his own arrival, the showing of the boat to a new-comer, and the start of the cruise generally, but as dinner progressed he began to feel there must be some more tangible cause for the excitement his friend was so obviously feeling. It was not Merriman's habit to beat about the bush.

“What is it?” he asked during a pause in the conversation.

“What is what?” returned Hilliard, looking uncomprehendingly at his friend.

“Wrong with you. Here you are, jumping about as if you were on pins and needles and gabbling at the rate of a thousand words a minute. What's all the excitement about?”

“I'm not excited,” Hilliard returned seriously, “but I admit being a little interested by what has happened since we parted that night in London. I haven't told you yet. I was waiting until we had finished dinner and could settle down. Let's go and sit in the Jardin and you shall hear.”

Leaving the restaurant, they strolled to the Place des Quinconces, crossed it, and entered the Jardin Public. The band was not playing and, though there were a number of people about, the place was by no means crowded, and they were able to find under a large tree set back a little from one of the walks, two vacant chairs. Here they sat down, enjoying the soft evening air, warm but no longer too warm, and watching the promenading Bordelais.

“Yes,” Hilliard resumed as he lit a cigar, “I have had quite an INTERESTING time. You shall hear. I got hold of Maxwell of the telephones, who is a yachtsman, and who was going to Spain on holidays. Well, the boat was laid up at Southampton, and we got down about midday on Monday week. We spent that day overhauling her and getting in stores, and on Tuesday we ran down Channel, putting into Dartmouth for the night and to fill with petrol. Next day was our big day—across to Brest, something like 170 miles, mostly open sea, and with Ushant at the end of it—a beastly place, generally foggy and always with bad currents. We intended to wait in the Dart for good weather, and we wired the Meteorological Office for forecasts. It happened that on Tuesday night there was a first-rate forecast, so on Wednesday we decided to risk it. We slipped out past the old castle at Dartmouth at 5 a.m., had a topping run, and were in Brest at seven that evening. There we filled up again, and next day, Thursday, we made St. Nazaire, at the mouth of the Loire. We had intended to make a long day of it on Friday and come right here, but as I told you it came on to blow a bit off the Coubre, and we could only make the mouth of the river. We put into a little place called Le Verdon, just inside the Pointe de Grave—that's the end of that fork of land on the southern side of the Gironde estuary. On Saturday we got here about midday, hunted around, found that old wharf and moored. Maxwell went on the same evening to Spain.”

Hilliard paused, while Merriman congratulated him on his journey.

“Yes, we hadn't bad luck,” he resumed. “But that really wasn't what I wanted to tell you about. I had brought a fishing rod and outfit, and on Sunday I took a car and drove out along the Bayonne Road until I came to your bridge over that river—the Lesque I find it is. I told the chap to come back for me at six, and I walked down the river and did a bit of prospecting. The works were shut, and by keeping the mill building between me and the manager's house, I got close up and had a good look round unobserved—at least, I think I was unobserved. Well, I must say the whole business looked genuine. There's no question those tree cuttings are pit-props, and I couldn't see a single thing in the slightest degree suspicious.”

“I told you there could be nothing really wrong,” Merriman interjected.

“I know you did, but wait a minute. I got back to the forest again in the shelter of the mill building, and I walked around through the trees and chose a place for what I wanted to do next morning. I had decided to spend the day watching the lorries going to and from the works, and I naturally wished to remain unobserved myself. The wood, as you know, is very open. The trees are thick, but there is very little undergrowth, and it's nearly impossible to get decent cover. But at last I found a little hollow with a mound between it and the lane and road—just a mere irregularity in the surface like what a Tommy would make when he began to dig himself in. I thought I could lie there unobserved, and see what went on with my glass. I have a very good prism monocular—twenty-five diameter magnification, with a splendid definition. From my hollow I could just see through the trees vehicles passing along the main road, but I had a fairly good view of the lane for at least half its length. The view, of course, was broken by the stems, but still I should be able to tell if any games were tried on. I made some innocent looking markings so as to find the place again, and then went back to the river and so to the bridge and my taxi.”

Hilliard paused and drew at his cigar. Merriman did not speak. He was leaning forward, his face showing the interest he felt.

“Next morning, that was yesterday, I took another taxi and returned to the bridge, again dressed as a fisherman. I had brought some lunch, and I told the man to return for me at seven in the evening. Then I found my hollow, lay down and got out my glass. I was settled there a little before nine o'clock.

“It was very quiet in the wood. I could hear faintly the noise of the saws at the mill and a few birds were singing, otherwise it was perfectly still. Nothing happened for about half an hour, then the first lorry came. I heard it for some time before I saw it. It passed very slowly along the road from Bordeaux, then turned into the lane and went along it at almost walking pace. With my glass I could see it distinctly and it had a label plate same as you described, and was No. 6. It was empty. The driver was a young man, clean-shaven and fairhaired.

“A few minutes later a second empty lorry appeared coming from Bordeaux. It was No. 4, and the driver was, I am sure, the man you saw. He was like your description of him at all events. This lorry also passed along the lane towards the works.

“There was a pause then for an hour or more. About half-past ten the No. 4 lorry with your friend appeared coming along the lane outward bound. It was heavily loaded with firewood and I followed it along, going very slowly and bumping over the inequalities of the lane. When it got to a point about a hundred yards from the road, at, I afterwards found, an S curve which cut off the view in both directions, it stopped and the driver got down. I need not tell you that I watched him carefully and, Merriman, what do you, think I saw him do?”

“Change the number plate?” suggested Merriman with a smile.

“Change the number plate!” repeated Hilliard. “As I'm alive, that's exactly what he did. First on one side and then on the other. He changed the 4 to a 1. He took the 1 plates out of his pocket and put the 4 plates back instead, and the whole thing just took a couple of seconds, as if the plates slipped in and out of a holder. Then he hopped up into his place again and started off. What do you think of that?”

“Goodness only knows,” Merriman returned slowly. “An extraordinary business.”

“Isn't it? Well, that lorry went on out of sight. I waited there until after six, and four more passed. About eleven o'clock No. 6 with the clean-shaven driver passed out, loaded, so far as I could see, with firewood. That was the one that passed in empty at nine. Then there was a pause until half past two, when your friend returned with his lorry. It was empty this time, and it was still No. 1. But I'm blessed, Merriman, if he didn't stop at the same place and change the number back to 4!”

“Lord!” said Merriman tersely, now almost as much interested as his friend.

“It only took a couple of seconds, and then the machine lumbered on towards the mill. I was pretty excited, I can tell you, but I decided to sit tight and await developments. The next thing was the return of No. 6 lorry and the clean-shaven driver. You remember it had started out loaded at about eleven. It came back empty shortly after the other, say about a quarter to three. It didn't stop and there was no change made with its number. Then there was another pause. At half past three your friend came out again with another load. This time he was driving No. 1, and I waited to see him stop and change it. But he didn't do either. Sailed away with the number remaining 1. Queer, isn't it?”

Merriman nodded and Hilliard resumed.

“I stayed where I was, still watching, but I saw no more lorries. But I saw Miss Coburn pass about ten minutes later—at least I presume it was Miss Coburn. She was dressed in brown, and was walking smartly along the lane towards the road. In about an hour she passed back. Then about five minutes past five some workmen went by—evidently the day ends at five. I waited until the coast was clear, then went down to the lane and had a look round where the lorry had stopped and saw it was a double bend and therefore the most hidden point. I walked back through the wood to the bridge, picked up my taxi and got back here about half past seven.”

There was silence for some minutes after Hilliard ceased speaking, then Merriman asked:

“How long did you say those lorries were away unloading?”

“About four hours.”

“That would have given them time to unload in Bordeaux?”

“Yes; an hour and a half, the same out, and an hour in the city. Yes, that part of it is evidently right enough.”

Again silence reigned, and again Merriman broke it with a question.

“You have no theory yourself?”

“Absolutely none.”

“Do you think that driver mightn't have some private game of his own on—be somehow doing the syndicate?”

“What about your own argument?” answered Hilliard. “Is it likely Miss Coburn would join the driver in anything shady? Remember, your impression was that she knew.”

Merriman nodded.

“That's right,” he agreed, continuing slowly: “Supposing for a moment it was smuggling. How would that help you to explain this affair?”

“It wouldn't. I can get no light anywhere.”

The two men smoked silently, each busy with his thoughts. A certain aspect of the matter which had always lain subconsciously in Merriman's mind was gradually taking concrete form. It had not assumed much importance when the two friends were first discussing their trip, but now that they were actually at grips with the affair it was becoming more obtrusive, and Merriman felt it must be faced. He therefore spoke again.

“You know, old man, there's one thing I'm not quite clear about. This affair that you've discovered is extraordinarily INTERESTING and all that, but I'm hanged if I can see what business of ours it is.”

Hilliard nodded swiftly.

“I know,” he answered quickly. “The same thing has been bothering me. I felt really mean yesterday when that girl came by, as if I were spying on her, you know. I wouldn't care to do it again. But I want to go on to this place and see into the thing farther, and so do you.”

“I don't know that I do specially.”

“We both do,” Hilliard reiterated firmly, “and we're both justified. See here. Take my case first. I'm in the Customs Department, and it is part of my job to investigate suspicious import trades. Am I not justified in trying to find out if smuggling is going on? Of course I am. Besides, Merriman, I can't pretend not to know that if I brought such a thing to light I should be a made man. Mind you, we're not out to do these people any harm, only to make sure they're not harming us. Isn't that sound?”

“That may be all right for you, but I can't see that the affair is any business of mine.”

“I think it is.” Hilliard spoke very quietly. “I think it's your business and mine—the business of any decent man. There's a chance that Miss Coburn may be in danger. We should make sure.”

Merriman sat up sharply.

“In Heaven's name, what do you mean, Hilliard?” he cried fiercely. “What possible danger could she be in?”

“Well, suppose there is something wrong—only suppose, I say,” as the other shook his head impatiently. “If there is, it'll be on a big scale, and therefore the men who run it won't be over squeamish. Again, if there's anything, Miss Coburn knows about it. Oh, yes, she does,” he repeated as Merriman would have dissented, “there is your own evidence. But if she knows about some large, shady undertaking, she undoubtedly may be in both difficulty and danger. At all events, as long as the chance exists it's up to us to make sure.”

Merriman rose to his feet and began to pace up and down, his head bent and a frown on his face. Hilliard took no notice of him and presently he came back and sat down again.

“You may be right,” he said. “I'll go with you to find that out, and that only. But I'll not do any spying.”

Hilliard was satisfied with his diplomacy. “I quite see your point,” he said smoothly, “and I confess I think you are right. We'll go and take a look round, and if we find things are all right we'll come away again and there's no harm done. That agreed?”

Merriman nodded.

“What's the program then?” he asked.

“I think tomorrow we should take the boat round to the Lesque. It's a good long run and we mustn't be late getting away. Would five be too early for you?”

“Five? No, I don't mind if we start now.”

“The tide begins to ebb at four. By five we shall get the best of its run. We should be out of the river by nine, and in the Lesque by four in the afternoon. Though that mill is only seventeen miles from here as the crow flies, it's a frightful long way round by sea, most of 130 miles, I should say.” Hilliard looked at his watch. “Eleven o'clock. Well, what about going back to the Swallow and turning in?”

They left the Jardin, and, sauntering slowly through the well-lighted streets, reached the launch and went on board.