1978. At a church volleyball match, Candy and Allan share a surprisingly charged moment on the court, while their spouses, Pat and Betty, navigate a misunderstanding in the stands. Though Candy assures her friend Sherry that Allan is "fall-in-love-proof," she later finds herself spontaneously proposing a first liaison. After initially insisting he can't cheat on Betty, Allan suggests he and Candy carefully weigh the pros and cons of an affair.

During Candy and Allan's second encounter, Allan recounts the impact of an earlier affair on his marriage and shares concerns that a now-pregnant Betty's postpartum depression may return. As their arrangement unfolds over the next several months, Candy fears she and Allan are at risk of breaking their most important rule - no feelings. Later, Candy bristles at news that Allan and Betty are going on a Christian marriage retreat.

After Allan tells Candy he needs to focus on his family, Candy is left to take another look at her own marriage - and suggests that she and Pat go on the same marriage retreat. Later, when the Gores and Montgomerys dine together, Candy finds she's completely over Allan. A sense of normalcy returns... until Pat makes a discovery that leads him to seek answers from Sherry.

Following a grisly struggle, a dazed Candy attempts to go about her day as normally as possible. Away on a business trip, Allan grows concerned when his repeated calls to Betty go unanswered. Later, Candy gives her version of events to the police, who also question Allan about the fidelity of his marriage.

After detectives intensify their questioning, Candy and Pat visit fellow church congregant Don Crowder, who quickly advises Candy to retain him as her attorney. At a funeral service in Kansas, Allan admits to Betty's relatives his affair with Candy... and that she's a suspect in the case. Later, Pat grows frustrated over being kept in the dark.

October 1980. After Don's explosive opening remarks reveal a strategy that shocks the community, Candy gets a visit from a furious and hurt Pastor Jackie. Later, Allan's testimony about Betty's state of mind rankles her father, Bob Pomeroy, and a series of witnesses describe the grim scene at the Gore house.