Accidentally on Purpose

After breaking up with her commitment-phobic boyfriend, Billie has a fling with a younger guy, ends up pregnant and decides to keep the baby – and the daddy.

While snooping through Zack's belongings Billie discovers a note addressed to her, that he never finished writing and sets out to find what Zack is hiding.

Billie's pregnancy makes her more attractive to members of the opposite sex, including Zack, who is turned on by her new curves. However, an unfortunate incident with self tanning lotion, forces Zack to reject Billie's advances toward him.

Billie and Zack discuss their feelings on dating and agree to see other people, however, Billie's pregnancy gets in the way of any potential love connections.

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.