Krakatoa, East of Java

In 1883, Krakatoa's volcano begins erupting, sending ash and shockwaves toward Sumatra. The eruptions terrorize the children at a mission school in Palembang, who fear for their lives as the sea and skies roil.

Captain Chris Hanson commands the Batavia Queen as it takes aboard a diverse cast including divers, balloonists, a mistress, pearl divers, and Laura Travis. He plans to salvage the Arianna's pearls and perhaps find Peter, setting the stage for jealousy and danger on the voyage.

Just before departure, colonial officials insist on transporting 30 convicts and their jailer to Madura Island. Hanson agrees to take them, but he allows one prisoner, Lester Danzig, to stay on deck, foreshadowing trouble to come.

During the voyage toward Krakatoa, observers notice seabirds in huge flocks, fiery explosions erupting from the sea, and a piercing hissing sound. The crew senses the ominous power of Krakatoa closing in as the sea grows volatile.

Danzig confronts Connerly about his lung disease and laudanum use, casting doubt on Connerly's ability to dive. He also hints that Laura's past might undermine her tale about the pearls.

The Borgheses locate the Arianna's wreck and guide the Batavia Queen and Rigby toward it. A malfunctioning engine cripples the ship's steering, sending them toward Krakatoa's crater. A volcanic explosion sets their balloon on fire, and they are blown clear and rescued at sea.

While divers work to free Rigby and raise the Arianna, Danzig seizes a pistol, frees the prisoners, and takes control of the hold. He holds the passengers at gunpoint as tensions aboard the Batavia Queen simmer toward catastrophe.

Hanson's team discovers the Arianna's safe is empty, containing only a cheap pocket watch. An explosion distracts Danzig, allowing Hanson to overpower him, and Rigby later uncovers a hidden logbook revealing the true voyage.

The logbook notes a Palembang port call where Peter may have disembarked to attend a mission school. Hanson steams toward Palembang to search for him.

Krakatoa erupts with escalating violence, hurling lava bombs into the sea. Toshi, one of the pearl divers, is killed when a lava bomb strikes the island.

When the Batavia Queen reaches Palembang, the mission school is heavily damaged and abandoned. The ship rescues the staff and students from a sinking sampan, and Peter is joyfully reunited with Laura.

Peter's chest of pearls is recovered and a portion of the fortune is distributed among the survivors. Krakatoa's eruptions intensify as a tsunami looms; Connerly and Charley join the lifeboat and row toward Anjer.

Krakatoa disintegrates in a final cataclysmic explosion, generating an enormous tsunami. The Batavia Queen rides out the wave with Hanson, Laura, Peter, Rigby, and the mission-school refugees aboard; Connerly and Charley perish as the sea claims them.