Comedy tracing the constant feud between Casey and her stepbrother Derek as they vie for control of their household.
Cast:Michael Seater , Ashley Leggat , Jordan Todosey , Danny Mags , Joy Tanner , John Ralston , Ariel Waller , Shadia Simmons , Arnold Pinnock , Kit Weyman , Robbie Amell , Shane Kippel , Kate Todd , Lauren Collins , Joe Dinicol , William Greenblatt , John Nelles , Michael Kanevsky
Sally is disappointed in Derek when he refuses to help out at Marti's birthday party; Casey asks Max if he wants to get back together.
Derek has trouble expressing his feelings, so Sally suggests that he write her a song. Edwin is hurt when no one finds his comedy routine for the talent show funny.
Casey sets out to prove Derek wrong when he claims guys and girls can't be just friends.
Casey and Derek choose to stay home alone while the rest of the family goes on a road trip to Quebec City for March Break.
Even though she tries not to care, Casey is crushed to learn the cute new guy, Truman, rated her a mere 6 1/2 out of 10.
Sally's acceptance into the University of British Columbia nearly puts a strain on Derek's relationship with her,... and everybody else. Lizzie and Marti take care of a lost dog.
All the kids are in crisis about going back to school in September, but they have to put their problems aside to stop Derek from dropping out of school to go west with Sally.
When Casey's dream diary - documenting her persistent dreams about Truman - goes missing, she's convinced either Edwin or Derek have taken it.
Casey spends a day at George's law office; Derek nearly loses business for Nora.
On gym activity sign up day, Derek (Michael Seater) makes sure Casey (Ashley Leggat) is late for school so all the popular options are booked up. Casey ends up in fencing, with Fergus (Patrick Garrow) as her instructor, and the insufferable flirt Truman (Joe Dinicol) as her partner. Although Casey and Emily (Shadia Simmons) had made a pact to swear off dating until after the Christmas exams, Casey now wants to extend the policy for the rest of the year just to keep Truman at bay. When he accidentally gooses her with his épée, Casey hits Truman on the arm with her épée and gets kicked out of fencing by Fergus. Meanwhile, George (John Ralston) brings home a new ping pong table and Edwin (Daniel Magder) beats all his siblings in turn except Derek, who considers himself the master and keeps cheating and taunting him. On Casey's advice, Edwin decides he can't lose if he doesn't play. Counter to the advice she gave Edwin, Casey begs Fergus to let her back into the class and he agrees, but only if she embraces the grace and beauty that is fencing. After some coaching, Casey decides she is ready to take on Truman. She also tells Edwin it's time he stood up to his big brother.
On her wedding anniversary, Nora tries to distract herself from George's Mexican fiesta fiasco by recalling Casey and Derek's plot to stop their parents' marriage.
When Ralph decides he's in love with Casey, Derek encourages him to go for it.
Derek threatens to ruin Casey's dreams of winning an important dance competition; Lizzie tries to convert junk food junkies George and Edwin.
After pulling a devious prank on Derek (Michael Seater) a year before, Teddy (Cameron Ansell) is back, hanging around, and driving everyone in the McDonald Venturi household crazy. Teddy knows they want to get rid of him, but before they send him home he appeals to Derek's ego as the master prankster. The only reason he's been hanging around and the only reason he pranked Derek last year was to earn his respect. A flattered Derek makes Teddy his personal assistant and Teddy has Derek exactly where he wants him. Edwin is deeply suspicious of Teddy's motives, and not a little jealous, but Derek won't listen to him. Teddy is now ready to make his move but is he good enough to outprank the master? Meanwhile, Truman (Joe Dinicol) promises Casey (Ashley Leggat) a first date she'll never forget and she gets it: the worst date of her life. Truman claims it was a joke but she isn't amused. To make it up to her, Truman lets Casey design the perfect date. Her date, her rules, his treat he's on!
With his D average, it's going to take more than supersonic cramming to get Derek into university.
Now that they've been dating for a few weeks, Casey (Ashley Leggat) and Truman (Joe Dinicol) have officially reached boyfriend/girlfriend status. So when Truman announces he's going to a private school party in Toronto that weekend, Casey assumes she's invited. But Nora isn't sure how she feels about Truman and doesn't like Casey travelling two hours to a party. Even though Casey volunteers to stay with her cousin Vicki (Paula Brancati), Nora still isn't comfortable with the idea. Instead, she suggests Derek (Michael Seater) chaperone. Casey is outraged at the idea, but that's the condition. Casey's not the only McDonald girl with a date Saturday night Lizzie (Jordan Todosey) has one too and with a boy Nora's never met. Nora figures Lizzie could also use a chaperone and finds Edwin (Daniel Magder) more than happy to oblige. Though Derek had intended to spend his time in Toronto hanging with his hockey buddies, he quickly changes his plans when he meets a cute girl while dropping Casey and Vicki off at the party. Unfortunately the night is less successful for Casey, who not only learns that Vicki and Truman used to date, but catches them in a kiss. Devastated, Casey finds support from a most unlikely source: Derek. Back home at Smelly Nellie's, chaperone Edwin is giving Lizzie's date, Marvin (Landon Norris), the third degree. Lizzie is furious and Marvin is very uncomfortable. Edwin finally does the right thing and leaves before Marvin does.
Prom is fast approaching, and Derek (Michael Seater) and Casey (Ashley Leggat) are scrambling to find dates. Casey had planned on going with Truman (Joe Dinicol), but isn't talking to him after what happened at the party in Toronto. And though Derek had a first, second and third choice picked out, when he finally gets around to asking, each girl has already committed to go with someone else. Casey decides prom will be more fun with a friend, and since her male pals are already spoken for, she asks Emily (Shadia Simmons) to be her date right before Derek hears that Emily is available and asks her himself. Emily tells him she can't since Casey asked first and is her best friend, though this is a hard decision after a surprise kiss reveals Derek has more than just a friend feelings for her. If he wants to take Emily to the prom, Derek's going to have to find someone else to take Casey and he thinks he knows just the person. George (John Ralston) and Nora (Joy Tanner), meanwhile, wait for an appropriate time to share a BIG secret with the family.
In the series finale of Life with Derek, Casey (Ashley Leggat) has been chosen valedictorian of her graduating class, but a case of "futuritis" has left her struggling to write her speech, which is supposed to celebrate the future. She has received a scholarship to Queens University in Kingston but is having second thoughts about moving so far away from her family. Derek (Michael Seater) claims not to be worried about anything he's planning to go to Europe the following year whether he gets into university or not. But he's having trouble convincing everyone including the principal, his girlfriend and his own father that he's not planning a prank for the graduation ceremony. Meanwhile, Edwin (Daniel Magder) is nervous about starting high school in the fall, worried that he won't live up to Derek's legendary reputation. After a discussion with his brother, he decides if he's going to make a name for himself at Thompson High, he'll have to pull off something big and fast! A prank at Casey and Derek's graduation ceremony could be just the ticket. The morning of the ceremony Casey has been up all night writing and rewriting her speech, and Derek is nowhere to be seen. Will Casey realize she has to speak from the heart? And is Derek really going to leave Edwin to carry on the 'prankster' torch alone?