SPOILER ALERT: Do not read if you have not yet watched “Heaven and Earth,” the 10th episode of the third season of “Outlander.”

Claire (Caitriona Balfe) is on the British ship The Porpoise treating crewmen who have contracted typhoid and much to her chagrin, the ship started moving away from The Artemis without her knowledge. Jamie (Sam Heughan) is the one who realizes the Porpoise is moving and demands the captain follow it. Captain Raines of the Artemis says British captain Thomas Leonard promised to deliver Claire safely to Jamaica. Jamie is enraged and almost roughs up Raines but when weapons are drawn, he stops. Raines has Jamie restrained, taken below deck and put in a cell.

On The Porpoise Claire commands the men to swab the decks and dip their hands in grog to attempt to keep the typhoid from spreading. A young British soldier, Elias Pound, who is only 14, says there are two prisoners on board who know how to distill whisky to make pure alcohol, which would help keep the infection from spreading. Elias also helps Claire feed and tend to the sick. He tells her he’s been at sea since he was seven years old. She tells him he’s a very impressive young man. Elias notices that his friend Jim Quigley has died and he closes the man’s eyes. Three more men are brought below deck — three new cases of typhoid.

Claire examines Captain Leonard’s log about the men who have become sick and notices they’re part of the carpenter’s crew and all but one have died. The young man who did not take ill is working as a galley hand. Claire tries to tell the ship’s cook that the galley hand can’t serve food because he’s a carrier of the disease even though he never got sick. The cook doesn’t understand what she’s telling him, but Captain Leonard orders the galley hand taken into custody, following Claire’s advice.

Back on the Artemis Jamie is locked in a cell below deck, telling Fergus (Cesar Domboy) he is worried about Claire being with 300 men on the Porpoise. Jamie says, “I lost her once, I cannot lose her again.” Jamie asks Fergus to get the keys to the cell and set him free. Jamie also wants Fergus to convince more men to join a revolt so the Artemis can chase the Porpoise and he can reunite with Claire once again. But Fergus says no, which causes Jamie to lash out, “Then you don’t understand what love is.” Jamie tears up and says if Fergus gets the keys to break him out, he’ll give his blessing for Fergus and Marsali to marry.

The Porpoise holds a memorial service for the men who have succumbed to typhoid. Prayers are recited and the wrapped bodies are thrown overboard. That night, Claire is on deck alone. One of the Brits, Cosworth, asks her what she’s doing about stopping the outbreak because there are 11 dead so far. Elias appears and tells Cosworth to go away. Elias asks how Claire remains so calm and she explains the concept of compartmentalizing, “If you let every death get to you, you’ll never save a life.” Claire says that with a little luck, they’ll make it to land without losing more men. Elias says with Claire on board, it’s not about luck but if it is, she should have his rabbit’s paw. Their conversation is interrupted with news that another man has taken ill. Claire realizes this man drank the pure alcohol she’s been using to sterilize everyone’s hands and medical instruments and therefore has alcohol poisoning.

Claire also sees a Portuguese flag covering a man and asks where it came from and was it from the ship called the Bruja? Claire looks for Captain Leonard to get an answer, but his office is empty. She goes in anyway and finds the captain’s log that says the ship was the Cacador. She reads more of the log and finds an item about Jamie being wanted for sedition. Then Cosworth enters and castigates her for entering the office even though the Captain wasn’t there. He blocks her from leaving the office and says she’s trespassing. Cosworth says, “I don’t like you and I don’t trust you. I have the captain’s best interests.” Claire says she has the captain’s trust and tells him to get out of her way or she’ll scream. Shaken, she leaves the office, resolving to find a man named Harry Tompkins, the man noted in the log who had recognized Jamie.

Fergus and Marsali (Lauren Lyle) talk as she cleans his fake hand. He says he has to rally men to help Jamie get Claire back so they can have his blessing to marry. They start to make out but, as she starts to unbutton his pants, he stops her and says they have to wait until they’re married — he promised Jamie they’d wait. Marsali says Fergus is stubborn, just like Jamie. Fergus kisses her again and goes.

Claire and Elias talk while she cleans her medical instruments. She asks if he knows Harry Tompkins and says he may be another carrier but tells Elias not to share that information. Four more men are sick. Elias says he won’t tell. She tells Elias to get some sleep.

Back on the Artemis, Fergus overhears Captain Raines talking about maybe throwing Jamie overboard. He sees the keys he needs to unlock Jamie’s cell but does not take them.

On the Porpoise, Harry Tompkins is brought to Claire. Tompkins says he knows who Claire is. Claire holds a sharp medical cleaver as she talks to Tompkins. He says, “Kill me, I’ll thank you for it.” Tompkins recounts going to Jamie’s print shop and finding the seditious pamphlets and getting acid thrown in his face by Young Ian. He says he made it out of there, scarred for life. He says his boss Mr. Percival pressed him into service on this boat full of disease instead of promoting him. Tompkins tells Claire that Jamie is also wanted for murder for the body they found in the cask of creme de menthe. Claire says Jamie didn’t kill that man. Tompkins says Captain Leonard is an ambitious man and he’ll want to turn in Jamie. Claire has Tompkins jailed in a cell and says he’s the second source of the typhoid. She warns Tompkins not to get too close to Howard, the cook’s hand who is the true source of the disease.

The wife of the man Claire saved from alcohol poisoning earlier gives Claire goat cheese to thank her for helping her husband. Claire confides in her that she needs to warn Jamie but doesn’t know how she can do that. The woman — Mrs. Johansen — says she’ll help and says she has to feed her goats. Claire is puzzled and doesn’t know what she is talking about.

Fergus tells Jamie he didn’t really try to get the keys to unlock him because he heard talk about throwing Jamie overboard. Jamie protests and says they will succeed in overtaking the crew. Fergus says he won’t leave Marsali alone or send Jamie to his death. Fergus says he’ll move heaven and earth for Marsali because he loves her. Fergus leaves the cell as Jamie calls out after him.

Claire tends to the sick and things seem a bit calmer now. She hears music and goes up on deck to find the men singing and drinking. She sees Elias in a hammock, he has a rash and is delirious and thinks Claire is his mother. Unfortunately, Elias dies. She puts his rabbit’s paw into the burial sack and she tearfully finishes sewing up the sack. His body is thrown overboard.

That night, Claire talks to Captain Leonard and says she missed the signs that Elias was sick. He tells her that her efforts have been heroic and there’s been only one new case that day. She says she’s worried because the ship is running out of drinking water. Then Mrs. Johansen and another man find Claire and tell her they’re near land, Grand Turk Island, which means fresh water for everyone and grass for the goats. Claire now understands that Mrs. Johansen meant that she will be let off the boat so the goats can feed, and Claire will go with her.

Once they’re on the island, Mrs. Johansen tells Claire to go look for Jamie, that she will tend to the sick and feed them. Claire thanks her and runs! She has her medical kit with her but, unfortunately, runs into Captain Leonard and a couple soldiers. Leonard says he’s in her debt but he cannot let her go back to Jamie. He says he’s duty-bound to report Jamie to the authorities in Jamaica. She pleads with him to look the other way. Leonard has Claire escorted back to the ship.

On the Artemis, Jamie sits in the cell and looks at photos of Claire. The captain says they need every able-bodied man to help steer the ship and Marsali vouched for Jamie. She tells Jamie to tell the captain he’ll help. Jamie gives Fergus and Marsali his blessing to marry in Jamaica. Jamie thanks Fergus, then does go to help the ship’s crew.

Back on the Porpoise that night, Mrs. Johansen leads Claire up on deck, points to land and tells Claire to go. Claire says she’ll drown if she jumps into the ocean in the middle of the night. Mrs. Johansen says the water will move her. She gives Claire a pouch of money. Claire sheds some of her clothing and Mrs. Johansen throws a couple barrels tied together into the water for Claire to use as a raft. Claire jumps into the water, ready to journey back to Jamie!

“Outlander” airs on Sundays at 8 p.m. on Starz.