Part One: In 1980, William and Laurel make plans but are downtrodden by failed activism, stunted finances, and their drug addictions. William promises to "make [their son] a family" if Laurel can't raise him. William leaves with his baby when the paramedics treating Laurel's overdose mention calling the police. Some time after abandoning his son at the fire station, he decides to go to the hospital after him. In the present, COVID-19 prompts Kevin and Madison to quarantine together; they start a relationship and announce her pregnancy to family members. Rebecca's clinical trial is postponed. Randall is unresponsive when Kate requests guidance for involvement in the George Floyd protests. Randall finds himself more able to open up to Malik than to his therapist, telling him the white Pearsons never discussed similar incidents. For their birthday, Kate, Kevin, and their families drive to the cabin, where Rebecca and Miguel are quarantined. Madison fears for the babies after a fall. Kevin proposes marriage, and reaffirms it after urgent care allays her fears.

The Big Three, as eighth graders, experience puberty. Kate thinks Stewart wants to get back together, but he's only interested in their school project; Rebecca encourages her to follow her heart. Their classmate Tanya flirts with an uncomfortable Randall. Jack encourages Kevin's weight training, remembering his own father's less supportive approach. Kevin secretly exercises more at night. In the present, Kevin and Madison struggle to connect until agreeing to be more open with each other; both share their lifelong body-image struggles.

Rebecca cannot resist tending to incessantly crying baby Kevin, who finally self-soothes after Jack physically blocks Rebecca from intervening. In eighth grade, Kevin wants to quit football after his coach criticizes him for not knowing the plays. Rebecca would let him; Jack says Rebecca's coddling has made Kevin "soft." Kevin overhears the discussion and asks Randall for help studying the plays. In the present, Kevin is flustered when his new film's director offers him no feedback. The director later tells Kevin that if he commits to a role, he could be great. Kate accompanies Ellie to her ultrasound. Ellie tells Kate she considered an abortion and is confident about the adoption. The conversation evokes a past experience Kate kept secret from her family; Kate tells Toby that after her breakup with Marc, she learned she was pregnant.

In 1998, eighteen-year-old Kate decides to get an abortion. During the mandatory waiting period, she visits her ex-boyfriend Marc. Despite his apologetic words, he is still dismissive and inconsiderate; she quickly leaves without confiding in him. She terminates her pregnancy, telling no-one. A talent manager invites Kevin to LA; he accepts, despite Randall's advice that it could endanger Kevin and Sophie's marriage.

In Louisiana, New Orleans, the Vietnamese man who emailed Randal about knowing his biological mother, Hai relates Laurel's life story to Randall and Beth. Laurel DuBois chafed under her conservative upbringing in an affluent Black family. She was closest to her ostracized paternal aunt Mae and her older brother, Jackson, who dies in the Vietnam War. To grieve, Mae tells her to scream in the lake; Hai, a Vietnamese refugee fishing nearby, thinks she is drowning and "saves" her, and they fall in love. Faced with her father's expectation that she marry his hand-picked suitor, Laurel asks Hai to run away to Chicago with her. He cannot abandon his parents, and she only has money to get as far as Pittsburgh. After her overdose, Laurel is sentenced to five years in prison for drug possession and is later transferred to California.

In 1963, Esther Pariente and Nasir Ahmed meet in Albuquerque and fall in love. Years later, Nasir's long work hours as a computer scientist frustrate Esther, until he explains that his data compression algorithm could someday enable them to instantly transmit video of their son to Esther's mother in Argentina. Rebecca and Jack take a romantic getaway to the cabin after the eighth-grader Big Three opt out. A burst pipe damages the kids' childhood artwork, embodying Jack's fears that the family is growing apart. Rebecca salvages a paper depicting their five hand prints, now running together; she tells him their family will endure despite changes.

Jack and Rebecca bring the newborn Big Three home. Stressed by an aggressive driver, Jack drinks whiskey and has Rebecca drive them. Each doubting their own parenting ability, they reassure each other. Randall and Beth are at ease bringing Annie home, but Randall upsets Beth by suggesting he'd like a son; they make up and he explains he wants a large family to make up for not knowing his birth parents. Madison defuses Kevin's argument with a paparazzo while bringing the twins home. He dreams Jack telling him not to repeat Jack's mistake of comparing himself to his father. Kevin and Madison formalize their engagement.

When the Big Three are infants, Jack vies for a promotion by covering an expensive work dinner. Jack acquiesces to Rebecca's decision to manage the family's finances. In the present, tensions flare at Randall's home. Malik seeks Randall's advice when Janelle's mother, Jennifer, wants to be involved in the baby's life; Randall tells Malik he wishes he had known about his own mother earlier, and he reassures Deja that he would never side with Malik against her. Tess thinks visiting Carol is more accepting than Beth about her romantic relationship with her nonbinary friend Alex. Beth believes Carol disapproves of her chaotic home, but after Carol admits she misses the domestic activity of a family, Beth invites her to stay indefinitely.

The Pearson family gets ready for Kevin and Madison's wedding. In the 1980s, Rebecca and Jack fight about him taping a baseball game over a Dynasty season finale Rebecca had been looking forward to watching. Deja finds out that Malik has been accepted to Harvard. Beth and Tess bond over accessorizing her dress after Tess explains how uncomfortable she feels. Toby gets a new job where he would need to travel to San Francisco for three days a week. Kate tries to quit her job, but her boss Phillip refuses to accept her resignation. Flashbacks of Madison's life are featured: her British mother left her at a young age, giving her a pair of earrings for her wedding day; during her teens, her distant father advised her not to be "so choosy" and settle for whatever relationships she might have; in 2016, Madison is sharply dumped by her boyfriend and after a food binge, she ends up in the support group where she met Kate and Toby.