Tara Gregson, suburban wife and mother, tries to lead a normal life with her husband Max and teenage children Kate and Marshall while suffering from multiple personalities.

Once "T" and "Buck" have been in the house, the subsequent cleanup is never easy. Kate gets frustrated when Tara tries to sit her down for "the talk" and Marshall is too embarrassed to have Tara help when he has problems at school. Feeling like she's failed as a mother, Tara turns into her third alternate personality, "Alice," the ultimate 1950s housewife who has a knack for using her Betty Crocker-like demeanor to solve any issue.

When Tara and Max can't connect in the bedroom, Tara worries Max may be more interested in her alters than her. After gaining reassurance from her therapist Dr. Ocean (Valerie Mahaffey), Tara plans a "sex date" with Max to get them back on track. Tara's sister Charmaine (Rosemarie DeWitt) recommends she meet her boss, Tiffany, for a potential mural project. As Tara prepares for her "sex date" with Max, the pressure becomes too much and she becomes "Buck." That night, "Buck" doles out advice on women and Max ends up male-bonding with his own wife.

Tara feels the best she's felt in a long time. She loves the mural she is working on and feels she's found a new friend in Tiffany. That night, while Charmaine, Tara, and Tiffany are out for drinks, Tiffany decides she wants to see one of Tara's alternate personalities and begins probing Tara in a way that turns ugly. Tiffany wakes up the next morning horrified when she finds the mural is destroyed and she suspects Tara.

Tara turns into "T" and takes off in her car. Max and Charmaine go after her, creating the perfect opportunity for Marshall to throw a party as an excuse to be near his crush, Jason. Charmaine, Max, and "T" all return to the house to discover a raging party going on -- the buzz gets killed in more ways than one.

Tara and Charmaine's parents visit for the latter's birthday, but they have a secret agenda.