Life with Derek is a Canadian television sitcom that aired on Family (English) and VRAKTV (French) in Canada and on Disney Channel in the United States. The series premiered on Family on September 18, 2005, and ran for four seasons ending it's run, on March 25, 2009. The series starred Michael Seater and Ashley Leggat as the two oldest children in a stepfamily. It ended with 70 episodes and 1 spin-off television film, entitled Vacation with Derek.
George Venturi (John Ralston), a divorced man from London, Ontario who had custody of his three children from a previous marriage: sons Derek Venturi (Michael Seater) and Edwin Venturi (Daniel Magder) and daughter Marti Venturi (Ariel Waller), marries a divorced woman named Nora McDonald (Joy Tanner), who has two daughters of her own from a previous marriage: Casey McDonald (Ashley Leggat) and Lizzie McDonald (Jordan Todosey). Up until that point, Casey was perfectly content with her life. Growing up as the oldest child in a household in Toronto, Ontario with only her mother and sister had suited her well and brought her up as a self-sufficient and independent young woman.
After George and Nora's marriage, the McDonalds moved in with the Venturis in London, Ontario. Casey was originally upset about having to move to London, Ontario from Toronto, a much bigger city (as shown in the episode "How I Met Your Stepbrother"), for many reasons including Derek, but she eventually got over her own problems and agreed to move there for Nora and George's sake once she saw how much they cared for each other.