On a Friday night in June, 1981, Jack Kimball, his wife Johanna and their friends Sara, Porter, and Tom "Z" Zimmerman are gathered in the living room, merrily watching some slides of their college days, showing them as peace activists. Their faces suddenly turn serious and their looks fall on Sara as one of the slides show her with her boyfriend, McBride. Jack apologizes for the slide and quickly turns the machine off. The following night, Jack wakes up from his sleep and finds his wife is missing. He goes downstairs and sees a kettle boiling on the fire. He turns down the flame and the house explodes in a thousand pieces.
The case is filed as accidental death due to gas leakage. In the present, the house is being renovated, and the forensic police find traces of an explosive behind the kitchen stove. The case is re-opened.
While the team discusses the case, Janie, Lt. Stillman's daughter comes in with her son, Sean. She asks her father to keep Sean for the night because she needs some time to talk to her husband about their marriage. Lt. Stillman agrees.
Det. Rush and Valens start the enquiries from Sara, who had paid for the couple's funeral but didn't show up on that day. Sara's gardening and Lilly comments her flowers are beautiful. Sara tells them they are orchids and that they symbolize the strength of a family. She also tells them she had seen Johanna and Porter arguing over Porter's job with a military contractor. He had threatened Johanna if she ever dared to drop by his workplace.
Vera and Jeffries question Porter. He tells them how that night, Z was drunk, and called Jack "Mr. Jones" after the name of a radical underground students' group, who used to place bombs in public places to protest against the Vietnam War. He tries to minimize his role in the Jones Family.
As Miller and Valens gather the police reports on the Jones Family, Lt. Stillman abruptly calls Miller in his office. It turns out he couldn't open Sean's juice box. Miller points out the straw and Lt. Stillman keenly watches his four-year-old grandson open the box and drink the juice. Miller softly mocks her boss.
Rush, Valens and Vera come up with information on Z being an expert of bombs and a keen Jones Family follower. Jeffries and Vera question Z, and he tells them about McBride, who – influenced by Jack and with some help from Johanna, Porter and Z – blew himself up on a public place killing many other people. Since then, Sara, who was particularly affected by McBride's tragic death, had a grudge against Jack.
The detectives turn to Sara, who tells them that Jack had received a phone call from McBride's father, pleading him to confess his share of responsibilities on his son's death. Jack wanted to go to the police. Apart from Sara, who wasn't involved in McBride's plan, they were all scared by Jack's decision because it meant sure jail. Since Sara wanted justice for McBride, the team focuses on Z and Porter, and tries questioning them separately, hoping to put them one against the other. Meanwhile, Janie drops in to take her son home and confides her problems to her father.
Z and Porter narrate how they all decided to vote whether or not they had to turn themselves in; the "no" won over the "yes", and Johanna's vote was decisive. Z also overheard Johanna and Jack arguing in the backyard about orchids, family and how any future project depended on Jack. Johanna had also been sympathetic toward Sara's health problems and had asked her to stay with them for a while.
The detectives get puzzled, but when Sara's fingerprints don't match with the 1970's ones, they realize that Sara is actually Johanna Kimball. The real Sara died in the blast and Johanna stole her identity. That's why she didn't show up on the funeral's day. Porter later on confesses it was all Johanna's plan and it was she who asked him to make the bomb. He did it because he was in love with her but then something went wrong and she, too, died in the blast. The cops tell him the truth – it was Sara who died, Johanna simply used him.
Finally, the team arrests Johanna who confesses her crime. Z and Porter are also arrested for helping McBride blow himself up. While Bob Dylan's Like a Rolling Stone is played in the background, Jeffries meets old Mr. McBride, and Lilly sees Jack at the vault.