Steam lifting off the midnight water. Great sheets of it, like selective fog. The deck wet and saturated, railings slick and dripping.

They could hear chattering on the decks above. Tense, worried voices. A long steady note, which to Zack sounded something like a scream.

The gala deck was swirling with pitchwhite steam. A few half-dressed students clutching each other in silence, looking petrified. There were more up on the balcony—a good two-dozen of them—shifting about nervously amid clumps of forgotten streamers and confetti.

No music. Party over.

'Oh my God,' Maya whispered.

Yet more steam was creeping up from the dormitories, the connecting tunnel lidded by an opaque and shifting barricade of white.

Zack thought about his brother.

'What happened?' Maya was asking.

No one seemed to know, staring right through her.

They found Kirby sitting alone at the juicebar, one hand massaging his forehead, eyes darkly lowered.

'What happened?'

He jumped, startled, then slowly clambered off the barstool gripping his beltbuckle.

'No tellin,' he said after a while. 'Look to me like a steam valve break.'

'What does that mean?'

'Don't know,' he shrugged. 'But whatever it was, it flooded the entire ventilation system.'

'With steam?'

He nodded.

'How bad could it be?' Maya wondered.

'You'd have to ask Mr Moseby.'

'Where is he?'

'Behind you.'

Zack whirled around, feeling a sharp tug on his right arm. Moseby had him by the elbow, snarling: 'What did you do?'

'Me?'

'You weren't at the party. Where've you been all night?'

'What's the big deal?' Maya blurted out. 'A little steam never hurt anyone.'

Moseby was trembling. 'It's superheated,' he grimaced. 'For powering the ship!'

Sloane cupped her mouth in horror. 'What does that mean?'

But Zack had heard enough.

Squirming free, he made a break for the dorms, for the immense shroud of white fog coiling up through the corridor. Maya yelled after him, but he wasn't listening.

His brother was in there. Bailey too.

Steam sluiced over his skin as he neared the tunnel. Ceiling dripping, air quivering. A dank, almost organic smell, like fresh mulch.

He lumbered on, arms outheld, zombie-like, knifing through the fog, fingertips probing bare walls for cardslots and doorknobs. He knew these halls—just not well enough to negotiate them blindly.

Already he could feel his face reddening, his hair beading with sweat, the heels of his pantlegs heavy and soaking. He tried to visualize Cody's door.

Slowly he rounded the bend at the end of the hallway, lungs burning. Air thick. Solid white. Impenetrable.

He slumped to his knees. Vision blurred, skin peeling.

Another cloud came rolling in, a great flowering mass. He shrank from it, shielding his face, the skin of his palms wrinkling up like boiled cabbage.

Seeing red.

Seeing black.

When he reopened his eyes he was on the ground, being dragged out by the ankles, floor scrolling away into the fog, taking the skin on his right cheek with it.

He awoke to Maya's shoulder, her arms coiled loosely around him, hands tracing little clockwise circles up and down his back. He sucked in a breath of cool air, then coughed it back up.

Maya let go.

'What happened?' Zack sputtered. 'Where's Cody?'

They were out on the lido deck, poolside, completely alone. Morning sun pale and red, balanced like a marble on the still-dark horizon. Above them a lone star-spangled banner whipped lazily southwest.

Maya smoothed back a loose strand of hair.

'Cody's dead, Zack.'

She'd said it flatly, without feeling, eyes tired and empty.

Zack laid back, the cement cold and wet beneath him.

For a long time neither of them spoke. The wind. The soft intermittent lapping of the pool.

Maya sat watching him think. She touched his peeled and bleeding hand.

'How many others?' he said at last.

'Something like nine hundred. Students. Passengers. Crew.'

Zack nodded. Tears welled in his eyes but did not fall.

'Sloane told Moseby everything,' Maya went on. 'But she couldn't account for the leak.'

'That's because I caused it.'

'Zack…'

'I remember.'

'It wasn't your fault.'

'Then whose was it?'

She gripped his hand, lacing their fingers. 'It wasn't anybody's fault.' And then: 'Not everything is knowable.'

'Some things are.'

She closed her eyes. 'I don't think I can help you.'

'I don't want you to help me.'

'Do you want me to leave?'

'No. I don't want you to leave.' He sat up, breaking her grip on his hand. He touched his face. 'How do I look?'

'You look fine.'

He scooched to the edge of the pool, studying his bent and shifting reflection in the water's surface. His right cheek was scraped raw, bleeding here and there. He lowered his hands to the water and rinsed them in a dense cloud of pink, then splashed a few droplets on his face.

'Do you still have the key?' he asked without looking up.

Maya hesitated. One hand slid slowly toward her pocket. 'Why?'

'I have to go back,' he said. 'I have to know for sure.'

'Know what?'

'If I'm responsible.'

They swiped London's card and heaved open the hatch. Zack went first, ignoring the puddle, ignoring the darkness, the engines' collective roar reduced to a low and sickly murmur. Eventually the lights flared up.

Maya followed closely behind him, along the catwalk and down the ladder. When they reached the maintenance hub on the platform below, Zack immediately stalked toward the leftmost control panel and stood surveying the surrounding area, the knobs, the switches, the blank and gaping surveillance monitors.

'What're you looking for?' Maya asked.

Zack didn't answer. He had his hands raised, framing the room between his thumbs and forefingers, as if attempting to visualize something. His eyes settled on a row of yellow and black striped levers to the right of the control panel, all but one of which were toggled upward. The remaining lever appeared to have somehow broken free of its safety latch and now stood partly lowered. An enormous yellowblack sign above the levers read in bold print: Danger.

He had only a few seconds to admire it before, with a familiar clatter, the lights blinked out.

Maya inhaled sharply, reaching for her phone. She lit the screen and swung it toward Zack. 'What is it with this place?'

Again he didn't answer. Head down, eyes averted, skin pale and blue against the dimming artificial light.

'Zack?'

'I'm pitiful,' he said at last, glancing up from the floor.

Maya remained silent.

Suddenly Zack flung up his arms. 'Isn't there anyone here?' he called out, as if addressing the shadows. 'Any forgotten spirits? Any restless souls? Anyone at all?'

No response.

He allowed his arms to fall limply to his sides. 'No one?'

'I'm here,' Maya put in.

Zack ignored her. 'I thought that maybe I was wrong. That maybe I'd find something down here. Someone. Anyone.'

'I'm here!' Maya repeated.

'You won't be for long. No one ever is.'

'What do you mean?'

Zack sat down in the floor. 'It's me,' he choked, his cheeks smeared finally with glimmering tears. 'No one can or will hold on.'

'I don't understand,' Maya whispered, inching closer.

'Do you want to know why I wasn't at the party last night?'

She didn't answer.

'The same reason I'm down here now,' he said softly. 'Because everyone I try to hold onto—' He made a fist, then abruptly opened it, as if spreading ashes. 'I was hoping that there might be someone else down here. Someone who could explain it to me.'

'It wasn't your fault,' Maya said again, her throat tightening.

'It had to be.'

'Zack…'

He was on his feet. 'How could I not be guilty?'

Maya leveled the light at him.

'I'm pathetic,' he snarled, turning to face the console.

His fist sprang up and dented the monitor nearest him.

Maya jumped.

A long spiderweb-shaped fissure forked out across the glass. Zack flexed his fingers, watching the blood funnel down between his knuckles, into his palm. His chest heaved in and out.

Maya stepped through the shadows. She closed her phone. She placed one hand on his shoulder, and in the other she took his wrist. Then she raised his knuckles to her lips and kissed them.

He wouldn't be abandoned again.

Later that morning the Miami coastguard arrived to begin ferrying survivors back to shore. Much of the steam had cleared, but some areas were still uninhabitable.

Zack and Maya sat together on the wraparound deck, awaiting evacuation. A good fifty people in line ahead of them, another fifty or so in back. The lifeboats could transport up to five at a time. They'd be fitted with PFDs and floated out across the water toward one of two patrolboats, then hauled onboard to safety.

When it was finally their turn to be lowered down to the water, the patrolman at the head of the line placed Maya in raft A and Zack in raft B. The little yellow vessels then set off rocking through the current.

Zack watched from the gunwale as Maya's face retreated slowly into the foam and the spray of the ocean, as the rafts parted ways, picking up speed.

It was January first. It had been for a long time.