'Bill – or Taffy,' he breathed.

A hand came out into the light and fumbled with the fastenings of the hatch cover. Ahead the men on board Sirena seemed to be watching the attempt to clear the mast or looking back towards Falcon, and there was a good chance that they wouldn't see a man if he moved stealthily across the deck. A wild dash would be suicide.

The disembodied hand was still working on the hatch cover. 'I'm going to undo the other side,' I said quietly to Geordie. 'Cover me.'

A rumble came clearly across the water from Falcon cutting through all other noises, and the red flashes of light in the black cloud suddenly flared higher. Voices were raised in alarm and there was a stampede of running footsteps. The diversion was well timed and I slid along the deck, clutching for the edge of the hatch, and pulled myself to lie close alongside. Groping for the catches, I saw that my companion was Bill Hunter. I had released one catch and was attacking the other when there was the sharp crackle of gunfire and a thunder of feet. Ian and Geordie were on their knees, firing at Sirena's men who were pounding aft towards us.

A contorted face loomed over me, the butt of a rifle poised over my skull. I jerked to one side and it slammed into the deck. Then I heard the distinctive 'spaat' of Campbell's target pistol and my assailant grew a third eye in the middle of his forehead and crashed on top of me.

I shoved his body aside and grabbed for the hatch. The second catch came free and Bill and I heaved the cover up and flung it open. Four men came boiling out of it, ready for blood.

Geordie screamed, 'Aft! Get aft!'

We all tumbled down behind the deckhouse. More shots rang out and Ian scored a hit. The rest of Sirena's crew retreated back to the mast as covering fire came from on board their ship. It seemed to come from their deckhouse, but it was hard to tell in the confusion. Geordie looked us over, counting heads and to my intense pleasure the face of Jim Taylor was amongst them. At least one of the dinghy crew was safe, which gave me hope for Rex Larkin. Bill gave roe a quick thumbs-up sign.

Sporadic fire came from Sirena. There was at least one sharpshooter up the mainmast, and Geordie ducked as a bullet sent splinters flying just above his head.

This is no good,' he said. There's not enough cover, and we're running out of ammo.'

Then came the methodically spaced shots from Campbell's pistol. There was a scream from the yardarm and a dark figure fell, all spinning arms and legs, to Sirena's deck.

Geordie got us moving aft, leaving Nick and Ian to cover our retreat. In the companionway Campbell was reloading the pistol as we swarmed below. His lips were curled back in a fierce grin. He motioned us aside curtly and aimed at the yardarm, crouching to steady himself in the hatchway. Another body plummetted down, this time into the sea.

'That's the lot,' Campbell said. He looked drawn and white and near the end of his endurance. In the passageway Clare was standing with her pistol held in a steady hand. The alarm in her face subsided when she saw us. I caught and held her briefly.

The men gathered below and there was a swift redistribution of weapons. Nick lifted a brawny fist. 'I won't need a gun,' he said. He was holding a huge stillson wrench.

A few more shots came from above but they died away, and a short time later Nick and Taffy reported that Esmerelda was clear of enemies below decks at least. With the exception of my brother.

Jim and Geordie went to reconnoitre the forward companionway, after a brief word with Campbell. Somehow he persuaded the Canadian to stay back in the saloon with Mark, Paula and Clare, and I forebore to ask him whether he'd done it by tact or threat. I was deeply relieved, either way.

'They've retreated – they're all aboard Sirena.' Geordie was back with a report. 'I didn't see any sign of Ramirez, but Hadley's all over the place, bellowing orders. He's making a right foul-up of the job too. We're still locked on, damn them.'

'What about Falcon?' I asked.

'The same as before – it's pretty fierce out there. But we've checked the engines and there's no sabotage there, thank the lord. We're going to have to get clear of Sirena and away bloody fast as soon as we can. But how?'

We all looked at one another, desperately searching for ideas.

Geordie swung round to Hunter. 'Bill, how did you get back on board? And where's Rex. Is he okay?' Bill didn't know about Danny yet, but I'd seen his eyes scanning our bunch and he looked grim. It took him a moment to reply.

'I'm sorry, skipper – we lost him. We saw some of Sirena's lot take over the launch. They held guns on our lads and threw them a line to haul them in. They hadn't seen us, so I got Rex and Jim here to slip over the dinghy side and we swamped her. Jim and I got back on board okay, up our ladder, but we had Rex between us and when Esmerelda lurched over he – let go. God, Geordie, I'

'You did your best. It's another one to chalk up to Ramirez,' said Geordie curtly. I left them together and went up to take another look at Falcon, feeling sick and depressed. The launch still bobbed at the end of its line, but somewhere under that twitching sea lay our dinghy and one of our crewmen.

The distance to the belching gout of smoke seemed less. Either we were dragging our anchor, which was very likely with the disturbance under her hull and the extra weight of Sirena alongside, or the area of eruption was enlarging – an even more alarming prospect. There was even more steam than before and I longed to know what was going on behind that red-lit misty curtain. I would have very much liked to ask Mark's opinion.

I went back down to Geordie. 'We've got to get out of here before Falcon really starts acting up.'

He looked across the sea. 'It's weird, I'll grant you, but is it that serious? Lots of observers have seen eruptions at sea before now. And Mark said it's been going on for days already.'

This is just an overture,' I said. No time now to begin a lecture on undersea vulcanology. 'I don't think we should be around when the finale's being played.'

'Oh, I want out too, make no mistake. But we've got a closer problem than Falcon right now – our friends out there. I wish to God I knew where Ramirez was, and what he's planning. Bill, could you see any sign of tampering with our hull? They've threatened us with explosives.'

Bill shook his head. 'No, skipper. At least not that I've seen.'

My warning about Falcon seemed to have passed Geordie by – it was something quite out of his experience. He was still wholly concerned with unshackling Esmerelda, and certainly for the moment he was right.

I asked, 'What the hell can we do?'

'Well, whoever's in command over there – Ramirez or Hadley – will want to get free as much as we do. They're in danger just as we are. And I don't think they'll find it so easy to retake us now, or blow us up as they threatened. Knowing Ramirez he may be prepared to cut his losses.'

'And try another time?'

'Another time isn't our problem right now. Let's solve this one first.'

He was right, and we waited in silence, aware that a plan was forming in his mind. At last he said, 'I reckon we should call a truce. If we send a man up the mast they won't fire at him if they know why he's going up there.'

'What's the good of sending one man up? They've had a dozen men up there for an age and they haven't been able to achieve much.'

'I've got an idea about that,' Geordie said, and passed the word for Jim to join us. 'Got any more of that plastic explosive, Jim?' he asked.

Jim shook his head. 'No, I only had the bit I used on their engine.'

Geordie pointed to the masts. 'See that yardarm – where it's tangled with rigging? Could you blow it off if you fastened a hand grenade on each side of the spar?'