Sarah's perfect life is turned upside down when she discovers that her husband is having an affair with her best friend, Charlotte. The Bad Mothers: Maddie, Danielle and Bindy encourage Sarah's small acts of revenge.

Sarah's efforts to get Anton released reveal that he has put them deeply in debt, but surely he's not a killer? Danielle is convinced that Charlotte's widower, the brooding Kyle, is a more likely suspect.

With Anton remanded in custody, and in a parlous financial state, Sarah struggles to get more hours and care for her kids. She also works to get closer to Kyle to find the truth about his alibi.

Bindy moves in with Maddie, but chafes at being a mother on probation. Danielle goes to war with the school lunch box nazi and this only brings her closer to Luke. Sarah finds the truth about Kyle's alibi, and discovers he was covering for his father-in-law. But he is angry to find that her interest in him was only to prove his guilt.

Sarah and Kyle are forced to bond over their kids. Xavier is failing at school and refusing to visit Anton in jail, and Julius seems to be suffering from depression. Danielle helps Sarah out with the restaurant and finds it's being mismanaged.

Tom is threatened by Danielle's return to work, while Luke is supportive. Danielle is tempted to stray, but a family crisis makes Danielle call off the liaison. Maddie has a new contender in the battle for custody: Connor, her son's sperm donor.

Anton's trial is approaching and Sarah has no fresh leads. As she reviews the evidence, she starts to fear that he might have done it. She's also attracted to Kyle. But someone starts spreading rumors about them.

The women hatch a risky plan to ensnare Charlotte's killer and prove Anton is innocent.