Accidentally on Purpose

Billie becomes pregnant after a brief fling with Zack, and she asks him to temporarily move in with him because he has no place to stay.

When her boss raises the question of who Zack really is, it prompts Billie to go on a fact-finding mission as to the true identity of her baby's father.

Billie's pregnancy creates an attraction from members of the opposite sex, while Billie feels her own results of her hormonal changes, but she becomes really befuddled when Zack rebuffs her advances.

Billie declares that she and Zack are able to see other people, but it's Billie who finds the dating scene a little rougher than expected, and Zack finds a conscience when he tries the waters, too.

Billie tries to live vicariously through Zack and Davis by offering up dating advice to them. However, things take a turn, when the objects of the boys' affection reveal their true intentions.

Billie and Zack have their first big argument after Zack tries to surprise Billie by installing a low flow toilet.

Billie unintentionally causes Abby and Nick to break up when she asks them to be Godparents. However, after a fun night on the town with Davis goes too far, Billie must stop Abby before she does something she will regret.

When Billie starts dating a colleague from her newspaper, Zack is unable to hide his jealousy.

Billie is threatened when James hires another film critic at the paper and sets out to prove how valuable she is.

When Billie and Zack take instructional parenting classes separately due to their schedules, Billie goes with Olivia and Abby. However, the course quickly becomes a competition when Abby outshines Billie at all the tasks.

Worried that she'll ruin Christmas - as she has in previous years - Billie tries to hide from her parents the fact that Zack is living with her. Meanwhile, Abby's husband, Nick, tries to impress their father.

Abby and Nick have their respective significant others spend time with Billie and Zack to prevent them from finding out about the surprise shower they are planning. However, their plan backfires when both Billie and Zack dislike their new buddies.

While everyone feels the pressure of corporate cutbacks, Billie feels like she has to write the story of her life for a cover story and Zack & Davis go into business for themselves.

Not wanting to sound like a nag, Billie manipulates Zack into doing chores around the apartment; however, her plan backfires when Zack takes the initiative to "decorate" the nursery. Meanwhile, to earn extra cash, Davis gets a job at a gay bar.

Billie invites herself to Zack's high school reunion but worries that she can't compete with his hot, ex-girlfriend in her pregnant state. Meanwhile, Olivia helps Abby host a party where they try to sell Abby's miracle youth juice.

Zack is upset when Billie hires a baby nurse without consulting him. Meanwhile, Davis and Ryan are faced with a difficult choice when they learn surprising news about the nurse.

Billie pretends to go into labor to save Zack from getting a traffic ticket after they're pulled over for speeding. Meanwhile, Olivia and Davis go shopping for a baby gift.

After faking labor pains to get Zack out of a speeding ticket, Billie goes into labor - for real. Unfortunately, things take a turn when Zack gets busted by the officer they had initially lied to and is hauled off to the police station.