Life with Derek is a half-hour comedy series about a modern blended family, with two type-A 15 year-olds, Casey (Ashley Leggat) and Derek (Michael Seater). Each episode is an alpha-teen comic war between two self-obsessed teenagers in a take-no-prisoners
Sally (Kate Todd) is disappointed in Derek (Michael Seater) when he refuses to help out at Marti's (Ariel Waller) birthday party; Casey (Ashley Leggat) asks Max (Robbie Amell) if he wants to get back together.
Derek (Michael Seater) has trouble expressing his feelings, so Sally (Kate Todd) suggests that he write her a song. Edwin (Daniel Magder) is hurt when no one finds his comedy routine for the talent show funny.
Casey (Ashley Leggat) and Derek (Michael Seater) choose to stay home alone while the rest of the family goes on a road trip to Quebec City for March Break.
Derek (Michael Seater) insists he's fine after breaking up with Sally (Kate Todd) but Edwin (Daniel Magder) and Casey (Ashley Leggat) are concerned about him.
When Casey's (Ashley Leggat) dream diary- documenting her persistent dreams about Truman (Joe Dinicol) - goes missing, she's convinced either Edwin (Daniel Magder) or Derek (Michael Seater) have taken it
On her wedding anniversary, Nora (Joy Tanner) tries to distract herself from George's (John Ralston) Mexican fiesta fiasco by recalling Casey (Ashley Leggat) and Derek's (Michael Seater) plot to stop their parents' marriage.