Sinbad and Tiger goes ashore and meets with the Professor. They haggle over the price to ship her cargo via the Providence
but the Professor eventually pays the new price. She tells them that she will expect a premium carriage service and goes to prepare. As Sinbad and Tiger leave, the Professor asks if there are any restrictions on luggage. Sinbad says that if it's larger than the ship then it will have to float, and the Professor says it doesn't. She then opens a door revealing a large egg, 10' tall and resting in a pool of water.
That night, the crew loads the egg aboard the ship and into the quarters while Gunnar worries that whatever laid it will be coming back. Sinbad explains that they need to find Tya Island to deliver the egg, and Tiger assures them that she knows where it is. Rina isn't impressed and figures that the Professor is paying well for more than a simple shipment. The Professor arrives and complains that they haven't put the egg in the hold, and Sinbad points out that it's not large enough. She also objects to them calling it an egg but refuses to say what it is other than egg-shaped. Sinbad tells Anwar to put the Professor up in his cabin while he sleeps with the others.
The next day, the Providence
sets sail and Sinbad and Tiger set out the route. He's surprised to discover she knows what she's doing and asks if she knows about the Land of the Dead. Tiger refuses to discuss it, but Sinbad asks her if she's lost someone she loves. The bounty hunter insists that she doesn't and Sinbad explains that he has lost his brother. Tiger admits that her father wanted a son and left her out on a rock, and tigers rescued her and raised her.
Anwar clears his things out of his cabin for the Professor and she sees his sketches of Rina. She dismisses him as a mere sailor until Anwar tells her that he studied at Basra Imperial College. The Professor wonders why he's on the Providence
and asks if his theories will change the world, and Anwar examines her cargo. He says that it's a vessel, not an egg, and wonders what it contains. The Professor says that it's paradise, inside the shell, and can eradicate any disease. It contains life essences, held in spores and placed within the shell. When Anwar insists it isn't possible, the Professor tells him that the release will be optimized by the time they reach the barren Tya Island. She can then release the spores and repopulate the island.
Sinbad goes to Tiger's spot in the ship with a flask of wine and discovers that she has nothing but a few blankets. Tiger comes up behind him and holds a knife to his throat, and he offers her something to drink. She accepts and asks what he wants, and Sinbad asks if she won't help him or can't help him. Tiger tells him that even if she could get there, there are places that the living shouldn't go.
In her quarters, the Professor makes sure that no one is watching and then opens a trunk filled with chemicals and medical equipment. She then uses a syringe to extract blood from her arm.
Later, the Professor orders Rina to get her a gourd of water. The thief complains to Anwar and points out that he's upset because he's met someone smarter than him. He assures Rina that the Professor is a genius, but Rina points out that Tya Island is inhabited and storms off.
The professor goes to the egg and injects the blood into it. When Anwar approaches her, the Professor hastily puts the syringe away. Anwar tells her that Tya Island isn't right for her experiment, but she ignores him when she realizes that the egg is in direct sunlight and overheating. She runs up to the deck and tells them to put it back in the shade or find themselves in breach of contract. No one is impressed but the Professor insists that they wash the egg with cold water every two hours. Tiger immediately agrees and invites her to eat, but the Professor complains about the nuts in the food and storms off.
Cook, offended by the Professor's aspersions, prepares a sophisticated meal and tries to take it to her. Anwar insists and brings the tray to the Professor, who is supervising Rina washing the egg. She takes Anwar to her cabin and asks him who else knows about Tya Island. Anwar assures her that only Rina knows and the Professor admits that the thief is right, but that the Tyans are a primitive race and perfect for her experiment. She tells Anwar that she has a confidential arrangement with the Tyans but asks him to bear witness to his work at the end of the voyage. Until then, she needs his absolute discretion as one scientist to another.
In the cabin section, a fly lands on the vessel. The egg cracks open, sucks it in, and reseals itself.
That night, Anwar takes his turn at watch and Rina reminds him to water the egg. She goes down to the sleeping quarters, briefly stroking the egg, and goes to the sleep.
The next morning, Anwar is asleep on his watch, having never watered the egg. Below, Rina wakes up and discovers that the egg has broken up... and whatever was inside is now gone. When the others wake up, they wonder if anything was ever inside. Anwar is sure that he destroyed the spores but Sinbad says that they should search. Crashing noises come up from the cargo hold followed by a shrieking noise. Sinbad tells Rina and Tiger to keep the ship on course while he goes below with Anwar and Gunnar before the Professor wakes up.
The three men go below and discover that whatever is loose has eaten all of their food supplies. Sinbad finds some kind of discarded snake skin… a dozen feet long. They hear another unearthly shriek and Anwar prepares to net whatever is responsible. A serpent, 10' long, lunges out of the shadows, missing Anwar and biting into Gunnar's arm. The Northerner throws it away and they run back to the ladder, sealing the hatch just in time.
When the Professor wakes up, she berates them as fools. The crew demands to know what the egg contained and Tiger assures them that they can still deliver it in a barrel. The Professor demands a description and confirms from the size of the bite mark on Gunnar's arm that the creature is fully formed. As the crew barricades the hatch and realizes that the creature is nocturnal, Tiger gathers pans to reflect the light and Gunnar starts to weaken from the bite. As the others help him on deck to get some air, the Professor calls Anwar over and says that they need to work together to protect her experiment. She claims that the island is infested with plague-ridden rats and the serpent was bred to eat them. Since the serpent hatched prematurely, it has changed and its blood is too concentrated. The Professor wants to thin the blood and asks Anwar to help.
On the deck, Sinbad and Cook treat Gunnar's wound and he insists that he's fine.
The Professor and Anwar open the hatch, believing that the creature has exhausted itself. They split up to search and the Professor gives Anwar a vial containing a liquid to release if he finds it first. However, once Anwar moves forward, the Professor climbs up and bars the hatch behind her. He soon discovers the hatch is sealed and cries for help, and the serpent closes in on him. Anwar throws a bag of food to distract it and continues yelling, and Sinbad and the others come down as the Professor hides. They get Anwar up and use the pans to shine the sunlight on the serpent, driving it back into the hold so they can seal the hatch.
Anwar goes after the Professor, who grabs him and holds a knife to his throat. She orders Cook to open the hatch and prepares to toss Anwar down, but the serpent grabs her by the arm and tries to pull her down. The crew manages to pull her free but the serpent rips off her arm before they can seal the hatch.
Gunnar binds his wound while an angry Anwar tells Sinbad that they should have let the creature eat the Professor. However, Sinbad points out that she's the only one who understands the creature. Rina goes through the Professor's notes and gives them to Anwar, and he realizes that she has been working with a radical professor who believes that humanity is flawed because of its compassion. He believed that a serpent would come and consume the weak of every species. The Imperial College exiled him but he continued his work, and Anwar realizes that the serpent will continue growing. They hear the serpent smashing around and realize that it will soon destroy the ship, and Sinbad says that they need to abandon ship.
The crew gathers everything they can and Gunnar puts the unconscious Professor in the dinghy. Cook refuses to abandon his ship. Sinbad tries to convince him to leave, but Cook says that if he drowns with it then it is his destiny. His crewmate refuses to accept that and insists that it isn't Cook's time. Despite that, Cook remains and when the others learn what he has planned, they decide to stay as well. Gunnar says that they need to survive until sunrise and then go after the serpent.
The crew battens down the hatches and lowers the boom. Rina tends to the Professor and the others wait until the serpent starts smashing through the hull. Tiger suggests that they use themselves as bait, lure it into the cage, host it up, and decapitate it. While they go to work, they fail to notice the Professor crawling across the deck to open the hatch. She then lets herself fall inside to feed the serpent, aware that it will become stronger the more it eats.
Sinbad tells the others to lower the cage while he's inside and then pull it up at his signal. However, he discovers that Tiger has locked herself inside and she insists that she can handle the serpent if it rips through the bars. Sinbad reluctantly agrees and they lower the cage. Once she's below in the crew quarters, Tiger emerges and searches for the creature. She finds it in the hold and realizes that it has started to look like the Professor. Tiger bars the hatch, and runs back to the cage. The crew pulls the cage up and Tiger grabs it and goes up with it. As they reseal the hatch, Tiger tells them what she saw. Anwar goes through the Professor's trunk and realizes that she gave it her blood and merged it with herself. Now the serpent has her intelligence.
Cook gets an idea and realizes that if the Professor and the serpent share the same strengths than they may share the same weaknesses as well. While the serpent slips outside and slams into the hull repeatedly, Cook gets the nuts that the Professor rejected earlier. He figures that the Professor is allergic to them and they can cause the serpent's throat to swell up by feeding the nuts to it. While the others prepare fire to hold the serpent at bay, Cook makes a mixture with the nuts and then spreads it on the three crossbow bolts that they have left.
The serpent breaks through the deck and Gunnar holds it at bay with a torch. Sinbad fires the first bolt and misses, and the serpent dives beneath the rising waters in the hold. Cook and Sinbad prepare the second bolt but the serpent grabs Anwar and drags him through the water. Gunnar pulls his comrade free while the serpent lashes out, knocking Sinbad down. He loses the second bolt, and Cook gives him the final bolt. Sinbad tells the others to lure it out of the water. The crew slashes at the water and it emerges, and Sinbad shoots it in the neck. Its throat swells, choking it, and Gunnar delivers the death blow with his axe.
The next morning, Cook serves eggs: the only thing the serpent left rather than engage in cannibalism. Tiger tells Sinbad that she knows of a monastery on the island of Malta that houses an ancient collection of maps that could lead him to the Land of the Dead.