'Yes, come in.'

Lieutenant Strang, busy plotting out something on a chart, looked up as the sentry parted the curtains of his cabin.

'Can Corporal Carrington see you, sir?' asked the man.

'Certainly. Send him in.'

Ken, looking more like himself in his khaki, which was now thoroughly dried, entered and saluted.

'Well, Carrington, what is it?' The commander's tone was quick, almost curt, yet there was a smile on his keen face as his eyes fell on Ken's upright figure.

'I've been talking to Othman Pacha, sir,' began Ken.

'Othman Pacha—who the deuce is he?'

'The Turk we rescued, sir. He's a friend of mine. I mentioned his name to you this morning. It was he who got me away into Greece when my father was arrested.'

'Of course. I remember now. But this is a most extraordinary coincidence—to find him on that tramp.'

'Not so much so as you might think, sir. You see he is known to be no friend to Enver Bey and the Young Turks. He was in danger of arrest, so he took the first opportunity of clearing out. He was going over to Adramyti on the Asiatic side, so as to get out of it all.'

'I see. Well, did he tell you anything useful?'

'He did, sir. You have heard that Enver Bey has informed our Chief Command that he intends to send French and British subjects to Gallipoli, so that they will be the first sufferers when we bombard the place.'

'Yes, I've heard that,' Strang answered, staring keenly at Ken.

'Well, sir, the Pacha says that the first lot is to leave Constantinople to-morrow. They are going with a batch of troops in a transport called the "Bergaz."'

'And,' he added—'my father will be with them.'

The commander of G2 pursed his lips in a soundless whistle.

'By Jove,' he said slowly, 'this is worth hearing. This is most interesting.'

He gave a low chuckle. 'Rather a smack in the eye for friend Enver if we can bring it off. Tell me, Carrington, did the Pacha say whether this trooper would have an escort?'

'I asked him that, sir, but he did not know. And he said this—That he would not have told us at all except for the fact that he thinks it brutal of Enver to send civilians into the firing line, and that he hopes, in case you find it necessary to sink the trooper, that you will allow the men to escape with their lives.'

Strang nodded thoughtfully.

'Hm, yes, I suppose I shall have to do that. After all, they won't be much use without rifles or kit, and the chances are that most of 'em will desert as soon as they reach the shore.

'But we mustn't count our chickens before they're hatched, eh, Carrington? We've got to find that transport before we can deal with her.'

He asked a few more questions, then dismissed Ken.

'You can tell the Pacha I shall respect his wishes,' he said, as Ken left his cabin.

All that night G2 cruised on the surface, going only at half speed so as to economise petrol, and at the same time re-charge her dynamos. As for Ken, tired out with his exertions, he lay upon the throbbing steel floor, wrapped in a blanket, and slept as peacefully as he had ever slept in his life.

It was broad day when he woke, feeling more refreshed than for days past, and quite ready for the plain though plentiful breakfast that was served out.

A glance which Williams allowed him through the periscope showed an expanse of bright blue sea sparkling under a clear sky and a light breeze, but with no sail in sight, and shortly afterwards G2 was submerged until nothing but her periscope remained above the surface.

By this time the rumour of the expected trooper was all through the little ship, and there was an air of subdued excitement on every face.

'Where are we now?' asked Ken of Williams.

'Somewhere between Marmora Island and Rodosto. Whatever comes out o' the Bosphorus for the Dardanelles is bound to run past us, and then—' A wink said more than words.

The hours dragged by, and Roy began to growl again at the tediousness of life beneath the ocean wave. Dinner time passed and still there was no sign of the trooper.

'Looks to me as if news had got abroad that we're a waiting for 'em,' growled Williams at last. 'Them chaps as got to land last night must ha' wired to headquarters.'

The other coxswain who was at the periscope at the moment, looked up.

'Then the wires must ha' been down, Joe. She's a coming right now.'

'Let's have a look,' exclaimed Williams, springing across.

'Ay, you're right, Bill. There she is. A big un, too!'

'And, lumme,' he added with a growl, 'a blighted torpedo boat a escorting of her!'

''Tis only one o' them tin Turkish rattle-traps,' said Bill with a pitying air. 'The old man'll slap a tin fish into her afore she knows what's hit her.'

As he spoke, the engines were already quickening, and G2 had begun to glide away at the top speed of her powerful electrics. The deep hum of the dynamos filled the long interior, and on every face was a look of eager expectancy.

As for Ken, his heart was throbbing like the dynamos themselves. The feeling that his father, whom he had hardly hoped ever to see again, was within a mile or so, had plunged him into such a state of tense excitement that it was all he could do to control it.

He turned to speak to Williams, but the latter had gone forward, and was standing by the torpedo in the fore tube.

The other coxswain, too, had gone to his place, and Sub-Lieutenant Hotham had taken his seat at the forward periscope.

For four minutes, which seemed to Ken like four hours, the submarine drove onwards in silence. Then came a sharp order from the commander, and she began to rise.

'What's she coming up for?' asked Roy of Ken in a low voice.

'She's got to, so as to fire her torpedo. You can't fire so long as you're submerged.'

'But if they see us, they'll let loose with their guns.'

'They've only got the periscopes to shoot at. Take more than Turkish gunners to hit them.'

'Stand by!' came the crisp order from Commander Strang. 'Three points to port—one more. Don't miss her, whatever you do, Williams. She's got the legs of us, and we shan't get a second shot.'

'That's right. Steady now. Shut down! Let go!'

Ken heard a sharp hiss as the compressed air drove the long gray Whitehead out of its tube, and sent it flashing away on its deadly errand. Young Hotham sat still as a statue, his eyes glued to the periscope. The rest of the crew seemed hardly to breathe. As for Ken, his mouth was dry. To him, more than to any one else aboard, the success or failure of the shot meant much.

Five, ten, fifteen seconds—then Hotham gave a sharp cry.

'Got her. Got her, by the living jingo! Oh, good shot, Williams!'

As he spoke a dull shock made the whole hull of G2 quiver.

'Hurrah!' shouted Ken, and the cheer was echoed by a score of voices.

'Struck her just aft the engines,' exclaimed Hotham jubilantly. 'Settled her hash all right. Gad, they've got pluck. They're still shooting. Ah, did you hear that, Carrington?'—as the submarine quivered again slightly. 'That was a shell. It struck the water not ten yards away.'

'But that's the last,' he continued. 'She's cocking her bows up. Phew, the whole bottom's knocked out of her. There she goes. She's sinking. Poor beggars, they haven't time to get out a boat, and we'll never reach 'em in time to save any of them.'

'Her stern's under. Bow's straight up in the air!' He paused a moment.

'All over,' he added quietly. 'She's gone.' Commander Strang's voice rang out from farther aft. Ken felt the vessel rising, and a few moments later a slight swaying told that she was on the surface. Up went the hatch, and the terrible clatter of the petrol engines replaced the deep purr of the dynamos.

'I'd give a finger to be on deck,' said Ken to Roy, and for once Roy did not jeer. He merely nodded, for he knew how desperately anxious Ken was about his father.

Ken had not long to wait. A few minutes later, an order was passed for Carrington to go up, and Ken darted up the steel ladder like a lamplighter.

Outside, he found the sun gone, the sky covered with clouds, and a threat of rain in the cool air. But it was not the weather he thought of. His eyes were at once fixed upon a large steamer about two miles off to the southward. Clouds of sooty smoke were pouring from her funnels, and a yeasty wake trailed away behind her. Taking warning by the fate of her escort, she was doing all she knew to escape.

'Will she beat us? Will she get away?' Ken asked anxiously of one of the gun crew.

'Will she spread her little wings an' turn into a waterplane?' replied the man with a grin. 'Bless you, soldier, she couldn't do more'n fourteen knots when she come out o' the builder's yard, and that's two more'n she's going now. You watch an' see how far she gets away.'

A very few moments' watching was enough to convince Ken that G2 was overhauling her prey hand over fist. Within less than a quarter of an hour a mile of the steamer's lead had gone. Another five minutes and the distance between the two was barely twelve hundred yards.

'Hallo, they're getting gay!' remarked the big bluejacket, as rifles began to spit and bullets to throw up little jets of spray around the rushing submarine.

Presently one clanged against the conning tower itself. Commander Strang gave an order, and a little row of bunting ran up on the tiny mast of the submarine.

'"Heave to, or I'll sink you," that means,' observed Ken's friend.

The only response was a thicker hail of bullets. But the low deck of G2, flying onwards as she was at about twenty-two land miles an hour, made a poor target, and the Turks failed to do any damage beyond knocking a little paint off.

'Confound 'em!' growled Strang. 'They haven't got sense enough to come in out of the rain. Give 'em a shell, Watson.'

The long gray 12-pounder was ready. Her vicious-looking muzzle swung round. There was a ringing bang, and the shell, small but charged with deadly lyddite, spun away on its errand.

Ken, watching eagerly, saw a bright flash light the side of the steamer, close under her stern, and as a cloud of smoke floated up, the crash of the explosion came back to his ears.

The big steamer staggered and yawed right out of her course.

'Capital!' said Strang with strong approval. 'That's hashed her steering. Signal 'em to heave to, or the next will be in their engine-room.'

There were a few more scattering rifle shots, but the officers on the transport soon stopped that. The transport herself, with her rudder in rags, was out of all control. Her engines were stopped, and she lay sullenly waiting for her saucy little enemy.

Strang gave a sigh of relief.

'Glad they had the sense to shut up,' he said to Ken. 'If they'd gone on shooting I should have had to sock it into them, and I didn't want to break my promise to your old Pacha.'

The submarine, smartly handled as usual, glided up close under the tall side of the transport, and Strang hailed her in French.

A black-browed officer, with angry eyes, came to the rail, and answered in the same language.

'You have British and French prisoners aboard,' said Strang sharply. 'You will be good enough to put them all into a boat and send them across.'

'And if I refuse?' retorted the other.

'I shall shell you until you think better of it,' was the calm reply.

The other bit his lips. 'Very well,' he said sullenly. 'I have no choice.'

'Look out for treachery, sir,' said Ken in a low voice. 'That man means mischief, I believe.'

'He is an ugly looking beggar. But what can he do?'

The words were hardly out of his mouth before the black-browed officer flung up his arm, with a pistol gripped in his fist, and fired straight at Commander Strang's head.

Quick as he was, Ken was quicker. As the man's arm came up, so did Ken's, and seizing Strang by the wrist, he jerked him back.

Before the man could fire a second time, one of the bluejackets had raised his rifle and shot him through the body.

'Thank you, Carrington,' said the commander, glancing at the gray splash of lead on the deck, just where he had been standing the previous moment, 'You were right, and I was wrong.

'Speak to them in their own language,' he continued coolly. 'Tell them I'll blow them out of the water if they try any more tricks of that sort.'

Ken's announcement was followed by dead silence aboard the steamer. Then a second officer appeared at the rail. He had both hands up.

'We surrender,' he said.

''Bout time, too,' growled the big bluejacket.

Strang repeated his former orders, and this time they were obeyed without hesitation. Ken's heart beat thickly as he watched the prisoners hurrying into the boat which had been lowered from her davits to a level with the deck.

'Do you see your father yet?' Strang asked.

'Not yet, sir,' Ken answered, with his eyes fixed on the fast-filling boat.

'Sixteen—seventeen—eighteen,' he counted mechanically. Suddenly a slight cry escaped his lips, and he started forward.

'Father!' he shouted loudly.

An upright man with keen blue eyes, a man of about fifty, but whose hair and moustache were almost white, was in the act of getting to the boat. At Ken's cry, he started violently, stopped short and stared incredulously in the direction of the sound.

'Father!' shouted Ken again.

'You, Ken?' The tone was one of utter amazement.

'It's me all right, dad,' Ken answered in a voice which shook a little in spite of himself.

Before their eyes the other seemed to shake off ten years of age. He sprang into the boat as lightly as a boy. Three more followed, making twenty-two in all. Then the blocks creaked, and the boat was rapidly lowered to the water.

Oars began to ply vigorously, and she shot across the intervening space, and a minute later was alongside the submarine.

'You must wait there, please, gentlemen,' said Strang courteously. 'I have to deal with the troops at once. Keep well astern.'

Ken was aching to greet his father, but there was plenty for him to do for the moment. He had to translate the commander's orders, which were that all those aboard the steamer should get away at once in the boats. He gave them twenty minutes for the operation.

They were the longest twenty minutes Ken every knew, but they were over at last. The crowded boats pulled slowly away in a northerly direction, the big steamer floated empty and helpless.

'Do we board her, sir?' asked young Hotham of Strang.

'Yes, I'll save my torpedoes while I can. Put a good charge of gun-cotton in her hold. Quick as you can, Hotham. We may have a destroyer down on us any minute. You may be sure they had plenty of time to use their wireless.'

He turned to the boatful of released prisoners. They were of every sort, young and old—French, English, with even one or two Russians and Belgians.

'Gentlemen,' he said briefly, 'I can't ask you all aboard. The reason is obvious. In a submarine there is only room for a certain number, and I am already three beyond my proper complement. The question is, what I am to do with you for your safety, and I should be obliged if two of you would come aboard to discuss matters with me. One whom I will specially ask is Captain Carrington.'

Ken's breath came quickly as he watched his father step across out of the boat on to the steel deck of G2, but like the trained soldier that he was, he did not move. Strang, however, had not forgotten him.

'You shall have your father to yourself as soon as we have settled things,' he said, as he passed him.

Mr Ramsay, who had been manager of a British bank at Constantinople, was the other delegate from the boat. He and Ken's father both shook hands with Strang.

'We are most deeply indebted to you, Commander Strang,' said Captain Carrington.' We never hoped for such luck as to find a British vessel already in the Marmora.

'Ours is unfortunately the only sort that can get through at present, sir,' said Strang with a smile.' And after all, I don't know that you have much cause for gratitude. I can't ferry you home through the Straits, for in the first place I can't carry you, and in the second I have my job to do up here. There is only one thing I can think of.' Here he lowered his voice, so that Ken could hear no more. But presently he saw the others nod, evidently agreeing to the proposal, whatever it was.