Life-changing events occur in the Season 4 finale, which finds the couples of Joss and Harry and April and Marc as new parents several months into the future. But one of their lives is turned upside down when a man from their past returns.
April is unsure how to announce her baby news to Marc just as his career is taking off; Karen reaches a relationship milestone when she meets Adam's parents, but her happiness is put in jeopardy when the Lydia situation resurfaces; Kate's anger at Joss shows no signs of subsiding, until she learns the truth about what really happened with Scott.
Karen fires Lydia when she uncovers her deception. Meanwhile, Harry juggles too many business opportunities; Joss and her impact-class pals want to avenge their friend's killer; and Marc resists April's attempt to reconcile.
Marc focuses on his music and bonds with Sofia. Meanwhile, Lydia tries to ruin Karen's new romance; April makes a decision after observing her mother's display of intolerance; and Joss deals with the death of a friend from her impact class.
April's mom causes trouble in April and Marc's relationship. Meanwhile, Karen meets a new guy after Lydia secretly sets up an online dating profile for her; Kate makes a change in her living arrangements; and Joss takes pills to cope with her anxiety.
April's mom arrives for an overnight stay, but she extends her visit due to health issues. Meanwhile, despite her misgivings, Karen makes an effort to bond with her new nanny; Harry deals with his sudden fame; and Joss learns that Kate is dating Scott.
Custody issues arise regarding Vivian. Meanwhile, April discusses a mature topic with Lucy; Kate keeps her new beau a secret from Joss and Harry; and Joss' actions lead to problems with Harry and land Jonathan's nephew in the hospital.
Alec visits unexpectedly and disrupts Karen's life with his news. Meanwhile, April and Marc clash on a parenting issue; Kate learns that her new beau has a connection to Joss and Harry; and Harry's business partner invites him and Joss to Las Vegas.
Karen stands up for herself in the wake of a bad interview with a shock jock. Meanwhile, April quits her job, but she lies and tells Marc she was fired; Joss and Harry struggle with their new working relationship; and Joss continues to battle PTSD.
Karen rejoices in work, even if it means making sacrifices in her love life. Meanwhile, April's new client disregards boundaries; someone from Marc's past resurfaces; Kate's displeased that her ex is moving on; and Joss aggressively pursues a new client.
Kate struggles with dating in Los Angeles. Meanwhile, Harry explores a promising new job venture; Marc helps April discover her true calling; the boundaries between Karen and Robert begin to blur; and the impact of the past year weighs on Joss.
Harry's sister arrives for a visit and reveals that all is not well between her and her fiancé. Meanwhile, Joss has trouble celebrating her own engagement; April learns about a painting fellowship; Marc joins a band; and Karen bonds with her male nanny.
In the Season 4 opener, Joss testifies at Wilson's murder trial a year after her perilous encounter with him. Meanwhile, Marc has employment problems; Karen thinks her male nanny is making advances toward her; and April fears Lucy is growing up too fast.