So far, the Nathan James has dealt with enemies from without: the Russians, El Toro, the Guantanamo terrorists. But this week, the threats come from within, as mistrust on board almost leads to mutiny.

In the communication room, sailors are having misgivings. One woman tells Granderson that others are asking questions—they want to know what’s going on. Granderson says the higher-ups would inform the crew if they heard anything about their families. Which is not a satisfying answer.

It’s dinner, but Slattery doesn’t want to eat—his appetite is still kaput after Nicaragua. Speaking of which, he’s wondering what they should tell the crew about their Central American adventure. Jeter thinks they should say they encountered hostiles, but leave out the bit about the village of starving sick people. Chandler isn’t sure it’s a good idea to keep secrets at all. But Slattery and Jeter are insistent: the crew needs hope.

Chandler visits Scott as she injects the monkeys with various vaccine prototypes. She explains the process: there are dozens of small gene mutations between the various samples she’s collected. “The key will be targeting the right one with the right combinations.” It will take anywhere from a few hours to a few days to know if any one prototype works.

Chandler makes an announcement to the crew. He tells them everything: about El Toro, about the slaves, about the sick people on the beach. “Yesterday, we couldn’t help them,” he says, “But perhaps tomorrow we will be able to.”

He also tells them they’re setting a course for home. And by the time they get there, he expects they’ll have a vaccine.

In their room, Tex teases Greene about his love life, claiming he knows which girl Greene likes. “I bet you 10 to 1 that she’s a lieutenant, and her initials are KFC, without the C,” he says. Greene is not amused. (Are these grown military men or preteen girls at summer camp?) Tex assures him he won’t share the secret, but Greene says it doesn’t matter—things with Foster are over.

Meanwhile, in another bunk, Foster and Granderson have a more business-like chat. Foster has caught on that something awful happened in Nicaragua. And Granderson says she’s not counting on a vaccine. On the upside, at least they pass the Bechdel test?

After an episode-long hiatus, Quincy’s back, and he’s pissy as ever. Despite having his requested chess partner, he still thinks it’s ridiculous that he’s being kept prisoner when he could be helping Dr. Scott. Bacon (his grumpy chess bud) says there’s nothing he can do to help—and even if he could, he wouldn’t.

But from the looks of things, Scott could use some help: the lab is now filled with bloody, dead monkeys. And Chandler is getting antsy. Shouldn’t she be closer to a vaccine by now? Scott says it’s all part of the scientific process—and that the virus is more complicated than she thought.

In any case, he tells her to toss the monkey corpses over the flight deck at night. And if anyone asks, to say it’s hazardous waste.

Chandler doesn’t want to waste any more fuel when they might have to turn back to Nicaragua for more monkeys. He tells Slattery and Jeter they’re going to stop the ship for a few days—and they need to come up with an excuse that won’t depress the crew.

Over chess, Quincy questions Bacon about why they’re stalled. Bacon says they’re just trying to determine the best place to manufacture the vaccine. Quincy, predictably, sees right through this. All the potential manufacturing labs are in North America—clearly Chandler is keeping things from them.

Like, say, the fact that Dr. Scott is tossing a whole bunch of dead monkeys overboard in the middle of the night. Although won’t remain a secret for long: as Scott undergoes her moonlit corpse toss, two sailors witness her in the act.

Back inside the ship, everyone’s on edge. Over cards, a sailor asks Tex how long it took them to get their masks on after they encountered the sick people in Nicaragua. Tex tells him to relax: no one got exposed.

But he may have spoken a couple of seconds too soon. Moments later, Greene walks through the door—and immediately collapses.

Scott busts into the room, claiming that Greene is not infected. Then he coughs blood into a rag. But Scott perseveres with her optimism: she says he was most likely just bitten by an insect.

The ship’s doctor arrives on the scene in full protective gear, and Scott says that’s unnecessary: if Greene is sick, they’re all sick. So Chandler demands a full set of tests.

Of course, panic spreads faster than illness. In the hallway, sailors are starting to whisper, while back in the rec room, everyone is starting to freak. Is Dr. Scott sure her test worked? What if the virus just showed up in his system now? Or what if it mutated and can’t be tested? Scott says she is 100% sure her test was accurate—but even Chandler can’t trust her. Against Scott’s wishes, he puts the ship on lockdown.

And since they all might die anyway, Foster breaks the no-fraternizing rule and rushes through the ship to find Greene.

Pulling on their biohazard suits, the sailors frantically question Jeter about what’s happening. Why was Scott throwing bags overboard? Are the monkeys spreading the disease? Jeter insists the disease is not spreading anywhere. Because it’s not even on board!

In his lab, the doctor tests Greene’s blood. Then he calls Chandler with uplifting results: it’s just dengue fever.

But while the ship is out of the doghouse, Foster isn’t. After everyone clears the room, Chandler reams her out over Greene—particularly their botched mission back in Guantanamo. “You took an oath,” he says, “and you have a duty to your shipmates.”

Seems a little harsh, if you ask me. The world is dying, shouldn’t these people find love where they can?

Now it’s Chandler’s turn to get a talking to. Scott stops him on the way back to the lab, and she’s not happy. She thought they had an understanding. She may have lied in the Arctic, but she’s being totally straight with him now—and when she says she’s 100% sure of something, she is.

Chandler interrupts, reminding her that he risked everything for her. “Not for me,” she says, “For the human race.” And if he doesn’t learn to trust her, they’re probably going to fail.

Quincy continues to manipulate Bacon, who admits there’s a lot of grumbling on board. So the British twerp outlines all the problems on the ship: the ventilation systems are crap, teams keep going into infected areas for supplies, the lab is not equipped to handle vaccine tests, and Dr. Scott has no clue what she’s doing. “This vessel is a death trap,” he says.

Speaking of death, Greene doesn’t look so good. Ignoring Chandler’s orders, Foster asks the doctor how he’s doing. The answer: not so good. His temperature is spiking.

Tex pays a visit to Scott’s lab. She needs a pick-me-up—after thinking she won Chandler’s trust, the lockdown definitely stung. But Tex has got her back. He tells her she’s going to figure it out. And Scott looks like she might be crushing.

Jeter barges in on a meeting between Slattery and Chandler. There’s a problem: 16 men want off the ship. Jeter understands their perspective. Their enlistments are up, and there’s no reason they should be forced to stay on board. But Slattery doesn’t look so sure.

Back in Quincy’s room, it becomes obvious who’s behind the mutiny: Quincy himself. Bacon can’t see why the captain would let Quincy go, but Quincy says they just need to make it clear that the men couldn’t survive on land without him.

As Chandler flips through Scott’s personnel file, the sailors discuss leaving. Two crewmembers try to convince Miller to come along, but he looks dubious. Suddenly, Granderson comes on the intercom calling everyone to the flight deck.

Once everyone has assembled, Chandler admits he hasn’t been up front—mostly because he wanted to protect the crew. But from now on, he’s going to share everything he knows. He plays the sailors some snippets from the radio, so they can hear how many distress signals are out there. These are the people they’re working to save with the vaccine.

Then he opens the door on Scott’s lab and invites them all inside. Scott explains that it might take many tries before she lands on the vaccine—but she will get there eventually. Then Chandler says that whoever wants to leave is free to do so the following day.

Post-speech, Tex approaches Chandler for a heart to heart. He thinks 16 guys is not that big a deal—they can get on without them. But Chandler doesn’t agree. “They go, hope goes with them,” he says.

Fortunately, it turns out to be a non-issue. Because the next morning, the sixteen men request to reenlist.

Chandler stops by the infirmary, where Foster is visiting Greene. He tells her that as punishment, she must devise a new training program for the engineering department. And she’ll have to explain to people why she was behaving so dangerously. She thanks him—but it still kind of seems like he could have gone easier on her.

And he definitely doesn’t go easy on Quincy. After his chat with Foster, Chandler charges into Quincy’s room and takes away his chessboard. No more fun for you!

Stats of the Week
Number of monkeys killed: at least 12
Number of times Quincy and Bacon play chess: 2
Likelihood of Tex and Dr. Scott hooking up: ’bout 100%
Number of pep talks Tex gives this episode: 2
Number of scenes that end with Chandler looking serious and/or pensive: 8