When Cooper's patient contracts measles, everyone at Oceanside Wellness must be quarantined. Meanwhile, Naomi tries to talk Addison into working with her rival, Wyatt; Violet and Pete contemplate their friends-with-benefits relationship; and Dell fights for custody of his daughter.

With her relationship with Kevin on the rocks, Addison finds herself attracted to Wyatt. Violet looks for a way to have a relationship with both Pete and Sheldon. Meanwhile, Cooper and Charlotte become closer after a family emergency.

Addison's brother, Archer, moves to Los Angeles to work at Pacific Wellcare; Cooper encourages Violet to discuss her pregnancy with Pete and Sheldon.

Addison suspects that Archer is up to his old tricks; a patient's child is born with male and female reproductive organs; Violet and Sheldon co-lead a therapy group for couples.

Addison flirts with a colleague at St. Ambrose Hospital; Sheldon and Pete try to convince Violet to take a paternity test; Sam accidentally calls Sonya by the wrong name.