We meet Elizabeth running through the UCLA campus in 1950 on the way to her Ph.D. qualifying exam. Explaining her scientific processes to a panel of older men, Elizabeth gives thorough, detailed answers to their questions.

After her exam, Elizabeth heads back to her lab, where she's met by Dr. Bates, her advisor, who says she knocked the panel's socks off. He kisses her unexpectedly, then locks the door despite Elizabeth saying she doesn't feel for him romantically. Dr. Bates quickly pins Elizabeth against a table and assaults her, but Elizabeth plucks a pencil from her ponytail and stabs it into his abdomen.

In a meeting with a department head, Elizabeth is told that Dr. Bates won't be pressing charges against her. If she shares a statement of apology, she will be allowed to continue with her Ph.D. candidacy. Elizabeth questions the decision, but it is explained to her as the most elegant option to move forward. Angrily, Elizabeth says she has one regret the incident – that she didn't have more pencils to stab Dr. Bates with.

In 1958, Elizabeth enters the Hastings Lab and asks Fran to reassign her to the Amminos lab. Fran says that's impossible, then lectures Elizabeth about her attitude, rejecting the request.

Elizabeth is conducting an experiment in the lab when Calvin comes in for the day. He's confused about what transpired between them, questioning it when Elizabeth explains that she's split the lab in half to accommodate them. Both are emotional, with Calvin leaving Elizabeth to work without him.

Elizabeth prepares a perfect meal at home but finds herself unable to eat it. After taking out her trash, she hears something outside and finds a dog rooting through her garbage can. She offers him food, finding the dog friendly as he refuses to leave.

At his home, Calvin is babysitting his neighbor Harriet's children, showing them a science experiment when she arrives to pick them up. Harriet asks Calvin if he can attend her next committee meeting to help push her agenda forward.

Dr. Donatti comes to the lab looking for Calvin, asking Elizabeth where he is and sharing that he needs to consider layoffs should Calvin not finish his work in time to secure the proper funding. Donatti threatens Elizabeth, telling her if he has to lay anyone off, he'll tell them that it was the fault of the woman who distracted Dr. Evans.

Elizabeth and her dog head to Calvin's the following day, where she can hear him in the backyard. Calvin is using a rowing machine in his garage, ignoring Elizabeth at first. She informs him that Donatti will start firing people if Calvin doesn't win the Remsen grant. Calvin explains he hasn't done anything productive since he won the last Remsen, but after meeting Elizabeth, he felt inspired. She apologizes but explains she needs the door open; she needs to know there's a way out. Calvin agrees he can do that.

Elizabeth and Calvin admit they miss each other, reaching a solid middle ground. Elizabeth shares that the dog's name is Six-Thirty. Calvin offers to teach her how to row, and they head to the water, quickly capsizing the boat. Both make it safely to shore, Calvin asking why Elizabeth didn't mention she doesn't know how to swim first.

Calvin tells Elizabeth he has feelings for her, but it's unfair to her as a scientist. As he suggests they work separately, Elizabeth kisses him.

At Harriet's meeting, she waits in concern for Calvin, who doesn't show up. Harriet makes her case on her own.

On the floor of their lab, Elizabeth works through her research to a dead-end before Calvin explains they should take a break. He takes her to a public pool and brings her into the water, doing his best to teach her to swim. The pair return to Elizabeth's later that night, where the couple has taken things to the next level in their relationship. In bed, they work through Calvin's notes, coming up with a breakthrough together. The pair decide to work through the Christmas holiday, staying in their lab instead of taking a break.

When Calvin and Elizabeth reach a proven breakthrough in their work, they celebrate in the lab, dancing and drinking together. They talk about their families, Calvin revealing he has no living family, and Elizabeth sharing she hasn't spoken to her parents since she was 17 by choice.

In the lab's cafeteria, Calvin prepares a Christmas dinner for Elizabeth while she gifts him a leash for Six-Thirty, offering to have him be Calvin's running buddy. Calvin asks her to move in with him, and she agrees tearfully—the two barter over how she can contribute to their household.

Calvin realizes he missed Harriet's meeting and apologizes, but she brushes him off and confirms it didn't go well.

At the Hastings Lab, Calvin and Elizabeth present their research, explaining that Elizabeth will be the first author of their project. The panel is hard on Elizabeth, belittling her until Elizabeth offers to take her name off the research. Calvin tries to fight her on removing her name from the paper, inadvertently telling her that he loves her in the process. Rather than allowing Elizabeth to be discredited, Calvin tells her they'll submit for the Remsen without Hastings' involvement, though he's unaware of anyone who's ever tried to do so.

Elizabeth and Calvin are talking about the future at home when she shares that she doesn't want to get married or have children. Elizabeth explains that she doesn't want to choose between her work and anything else and that women are expected to do just that. Calvin says if she's happy with him, that's enough for him.

As Elizabeth is making dinner, Calvin takes Six-Thirty out for a run. When the dog pulls on his leash more than usual, seemingly warning Calvin, he steps back into the street. A bus, seemingly out of nowhere, hits Calvin and keeps driving.