Frowning at the guttural Greek voices, I leaned on the stern rail and tried to recapture my thoughts. Safely away from the shore, the Pelagios was now catching enough breeze to leave a visible wake. Behind us lay the island where we'd stayed for the last month, held prisoner by an insistent wind that had risen to push us back each time we had tried to leave.

But our escape wasn't the main thing on my mind. It was what I'd learned, just before we'd pushed off the beach. My sister was alive! I felt a rare smile lift the corners of my mouth. For months I'd been certain Melantha was dead, killed by the same Greeks who had enslaved me. Now that I knew she was alive, I was going to find her.

Voices interrupted my thoughts again. "Never seen that before. Faster than us, sure. Maybe slower, maybe going another way. But following us? Never." I sighed and turned my head to see Lycos and Lycourgos, two of the younger Greek soldiers, gazing anxiously upward from the rear rowing bench.

Directly behind us, a small black cloud hung low in an otherwise blue sky, hiding the sun. Sitting idle at their rowing benches while we were under sail, the rest of the crew were muttering, casting anxious glances skyward.

Up in the bow, Lopex, commander of the Greeks, reached a decision. "Out oars, men!" he called. "Phidios, set a pace. Procoros, same direction." Waves began slapping at the hull as the oars bit into the water, but it quickly became clear that the cloud was keeping up with us. I peered up at it and shivered. Was I imagining things, or did the centre of the cloud look like a closed eye? I'd hoped that by escaping the island, we had also evaded its curse, but now, with the cloud above us, I knew with sick certainty that we hadn't.

Lopex was studying the cloud carefully from the bow deck. He gestured to Zanthos, who obediently twisted his steering oar in the water to take the Pelagios on a gentle turn to starboard. Not much, but enough that the wind could carry the cloud past us to port.

It didn't. As every eye on the ship watched, the cloud visibly changed course, tracking us. The ship began pitching more heavily, and I realized the wind was picking up, spume blowing off the tops of the waves.

Maybe the fates had already judged us. Perhaps what came next would have happened anyway. Just the same, Lopex's next move was exactly the wrong one. "Adelphos and Polites, furl the sail! Port side rowers, backwater on my signal! If we can't outrun it, let's see if it can turn corners!" He waved to Phidios, who immediately began the stiff-armed gestures to synchronize the new rowing pattern.

For a heavily laden ship, the Pelagios turned quickly, bringing us around into the wind, now rocking the ship with regular heavy gusts. "Both sides, standard row! Watch Phidios! GO!" Lopex roared over the rising gale. All eyes were turned upwards, mouths moving as each man prayed to his favourite god that the cloud would pass us by.

The gods weren't listening. Turning into the wind left us nearly motionless, despite the exertions of the sweating rowers, and the cloud caught up immediately. I held my breath, hoping it might yet blow past, but as it reached a point directly overhead, it stopped. The Greeks peered up fearfully as the cloud began to grow, filling the sky above us like the slow wingspread of a monstrous hunting bird. It spat a sudden torrent of hard rain at us, rain that stung as it struck.

As I clung nervously to the stern rail, watching Zanthos the steersman struggle with his oar, the men began clamouring even louder, their oars dropping unnoticed from their hands to foul the others.

Directly above us, the eye in the cloud was opening.

A furious orange light blazed down as though the sun itself was gazing angrily at us. The sun? The blood drained from my face as I realized whose eye was above us. I curled into a ball at the stern, hoping it would be over soon, damning the fortune that had bound me to Lopex. Why had I been permitted to learn that my sister was alive, only to be destroyed now by the wrath of Helios, god of the sun?

The cloud rumbled. A bolt of lightning, blinding white, leapt from the sky to strike the mast with a massive blast that battered my ears and left me deaf. In the moments to follow, hearing nothing, I saw the end of the Pelagios and its crew as if watching a silent play. The mast had exploded like a pine knot in a giant's fire, spraying flaming chunks of wood in all directions. A ten-foot length tumbled backward and smashed into Zanthos as he struggled with his steering oar, ripping a gash across the side of his face and neck before smashing him through the rail into the water. The wooden spar that spread the sail was sent spinning into the forward rowers like a huge saw-edged discus, ripping through men and ship alike before escaping through the starboard railing. Lopex had his mouth open, still shouting orders from the bow but the rowers had given up, cowering in terror beneath their oars.

A second bolt of lightning smashed the bow like a titan's club, shearing off three feet of the prow and leaving the hull open to the sea. Facing directly into the wind, the gaping hole instantly began taking on water. The bow pitched sharply lower and the men began leaping overboard, choosing Poseidon's unlikely mercy over the sun god's certain wrath.

Helios was not yet done with us. A third bolt struck the ship close by me at the stern. I could smell burning flesh and hair, and looked down to see my palms blackened, my arms and chest blistered as though the lightning's fire had travelled through the rail to reach me. The same bolt had somehow burst the ship along its keel, and as I stood on the stern deck the two sides of the ship slowly split apart like a giant clamshell, spilling spoils and despoilers of Troy alike into the sea.

The shock as I plunged into the cold water brought me back to the moment, the water excruciating on my scorched skin. I kicked frantically, struggling to remember the swimming lesson one of the Greeks had given me. As each wave held me briefly on its crest, I could see the heads of other men bobbing like seagulls as they struggled and drowned around me, surrounded by floating pieces of our shattered ship. More tongues of lightning flickered from the cloud, seeking out and striking the floundering men. A wave of salt water forced its way down my throat. Coughing and gagging, I began to slip under the waves, when something bumped the back of my head.

I twisted around. My healer's box! I grabbed at one of the handles, but my burnt palms were too weak to hang on. I threaded my arms through the thick rope loops, hoping they would hold. Another wave kicked me to its crest, and I saw Lopex nearby, struggling to climb onto a broken piece of decking before another wave swept it from him, dropping him into its trough, where he vanished.

My hearing was coming back. From all directions came gasps and shouts as the Greeks struggled and died, skewered by lightning bolts that hunted them down amid the waves. Overwhelmed by the horror around me, I hardly reacted to the discovery that my healer's box was riding lower in the waves. Exhausted, I tried to tug my arms from the handles.

Something was wrong. My arms were caught fast. I tugged harder but the rope loops had swollen in the salt water, tightening and binding me to the box. Packed with heavy clay flasks and jars and now full of water, it was slipping beneath the waves, pulling me down. I clamped my lips shut as I was dragged down, but in my exhaustion I couldn't hold my breath for more than a few moments, and it escaped from my mouth in a rush. I looked up to see the last bubbles of my breath, winking in the fierce sunlight as they spiralled toward the surface like tiny silver fish.