Accidentally On Purpose

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

Billie discovers an unfinished note addressed to her in Zack's belongings and sets out to learn what Zack is hiding. She realizes she doesn't know much about him and tries to get to know Zack better.

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 agree to see other people after discussing their feelings on dating. However, Billie's pregnancy gets in the way of any potential love connections.

Billie tries to live vicariously through Zack and Davis by offering them dating advice. 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.