“Knock itself out?” Jack shook his head. “Unlikely; these guys have a head that’s all cartilage and muscle mass. In humans, we’re about forty per cent muscle; but in sharks it’s typically eighty-five per cent. It’s a living torpedo, with its own armor plating.” He looked over the side as another titanic blow came from directly below them, lifting them in the water.

“Committed,” was all Valery Mironov said, as he looked from one of the windows.

“It’s denting the plates. If it hits twice in the same area, we might get a breach.”

“Ah, Jesus Christ.” Vincent threw his hands up, and looked skyward. “Can we get a break here?”

Cate looked panicked. “That’s it; we’re outta here.” She spun to Sonya and then Jack. “Sorry, but this is over. If this thing starts to sink, I am not going in that water. We need to be off, now.”

Jack grabbed her and hugged her in close to his chest. He looked over her head to Vincent. “Get that chopper in Vince – fast. Let’s at least get some of us back on dry land.”

“Yes, now might be a good time for a mayday.” Mironov turned back to them.

“Yep.” Vincent raced up the steps to the bridge.

Jack held Cate back a step. “You okay?”

She nodded and paced away, her arms wrapped around herself.

Jack watched her for a moment and then he, Sonya and Mironov went and looked over the side. Even though the lights only seemed to reflect the black water below, they were actually seeing down quite a few fathoms. The huge torpedo shape glided underneath them, barely moving its body at all.

“Shit,” Jack whispered. It was even bigger than he remembered. He knew sharks, and he knew their territorial instincts meant it would never give up until the Slava was gone, or laying on the sea bottom.

It finished its pass, having rolled in the water slightly, and he had seen the absence of claspers underneath the torso – female then. But there was something else in its shape that worried him.

“Can’t be,” he whispered. Jack exhaled and leant back. He still remembered Greg Jamison, and he damn well wasn’t going to allow Cate or himself to end up the same way. At the very periphery of the spotlight’s illumination he saw a huge lump rise from the water, to hang there, motionless.

“Can you see that?” Jack asked, feeling his heart race in his chest. He’d spent his entire life dealing with sharks of all shapes and sizes, but at that moment, he knew fear – the Megalodon shark was looking at them – it had lifted its head from the water, and those soulless black orbs were fixed on the people, not the boat.

“Oh yes,” Mironov responded softly. “I think it’s counting us.”

“Shit,” Sonya breathed.