Aboard the Antares, Donner and Zoe have the same dream Donner dreamt before where Zoe leaves the Antares.
The following morning, the crew meets for a morning briefing. At the end of the meeting, they take a moment to last look at the Earth before they are too far away.
On Earth, a press conference regarding Ajay and Rollie's exit is held. Trevor Williams, a journalist, wants to know what exactly happened, but Mike Goss avoids an answer and asks them to respect the astronaut's privacy. After the conference, Ajay and Rollie watch Paula Morales' report from the Antares.
Five years earlier, the candidates' basic swim skills are tested. Donner explains that anyone who fails this test will leave that day that program and Wassenfelder reveals to Ajay that he is not a swimmer and won't be able to pass the test. In the meantime, Jen tries to convince Zoe to abort the pregnancy.
In Jen's lab, Paula and Jen argue about Jen's experiment which involves destroying embryos of rabbits when Donner stops by to tell Zoe that they want to test her Venus suit.
On Earth, Eve tells Rollie that they will put Ajay and him on blood thinners because they believe the clot will resolve on its own. Rollie wants to know why It took so long to reject them both and Eve answers she doesn't know, but all they can do is follow its lead. Eve reveals that Ajay won't join the mission control on Earth because they won't let him pass the psych evaluation after his space walk.
On her way to the space suit test, Zoe hears the baby cries again.
Five years ago, Zoe is at her psych evaluation. That evening, Donner, Ted and Rollie find her in a bar where Zoe is drinking because she thinks she blew the test. When Zoe goes to the ladies' room to wash her face and opens up to a woman in there, Donner follows to hit on her.
Back on the Antares, Zoe is in the Venus suit to check out the critical operating systems and most importantly to check for leaks. In the meantime, Ted and Eve talk to each other. Ted is still dealing with the recent information they gave him about the true nature of the mission. He wants to know why It waited that long to get Donner and him on the Antares, but Eve can't answer his question because there is so little they know about Beta. She asks him to visit Pod 4 so It can give him an answer itself.
Nadia visits Steve and asks why he's on the Antares when he could do his work on Earth. Steve reveals that asks himself that question every day himself and that he should never have made it through the program.
On Earth, Eve watches the psych evaluation of Ajay where he explains his behavior on the Antares after he was told he had to leave. Mike Goss joins her to ask her how Ajay is doing. She answers sane and moving and adds that it won't get him back.
Zoe's suit is tested. Before Donner, Paula and Evram leave Zoe in the airlock in her Venus suit, Donner tethers and explains that airlocks make him nervous lately. Meanwhile, Ted is preparing to enter Pod 4. Suddenly, the airlock hatch opens and the pressure blows her out.
Five years earlier, back in that bar, Zoe blows Donner off. When he follows her to bring her a card she forgot, they have sex. The next morning, Zoe explains that she drank because she thinks she didn't pass her psych evaluation for the space program. Soon later, she receives a call that she is in that program.
A little later during the swim test, Jen finds out that the father of Zoe's baby is in the program. Meanwhile, Steve jumps into the water and goes under, but Zoe who was a life guard rescues him. When she argues with Donner who tried to help but hindered her rescue, Jen realizes that Donner is the father of the baby.
Out in space, Zoe finds out that her suit is losing pressure. Donner gets into his suit and pulls her back in, but he is running out of time when Zoe's speech is slowing down because of the pressure loss. The crew aboard and on Earth try to find a way to prevent Zoe from suffering from brain damage, and Steve comes up with the idea to let Zoe spit to slow the loss of air through a micro leak. Fortunately, it works.
Five years earlier, Eve and Mike go through the swim test results. When they come to Wassenfelder who failed, Eve tells Mike she wants him to pass. Mike argues that Wassenfelder can't swim, but Eve tells him to teach him.
Back on Earth, Eve and Claire tell Ajay that he is out of the program and that they will find him something to work on in research.
Finally, Ted opens the door to Pod 4 and is confronted with the surface of Mars.