In the Series finale, Stewart gets sidelined during Dean Sr.'s malpractice trial and it's up to the rest of the Sanderson & Yao team to save the firm and discover the secret mastermind behind Cory Manler and Dean Sr.'s case.
Dean and Stewart's mother visits unannounced, which sends Dean into a panic since she's never been a fan of his lifestyle. Meanwhile, Stewart is desperate to snare a reservation to a hot restaurant in town for his anniversary; and having his ex-wife in town spurs Dean Sr. to get back into the dating scene, with help from Ethan and Lizzie.
Dean loses his ability to grind after therapy, so he tries to solve the case of the office being ransacked. Meanwhile, in flashback, a young Dean must decide whether to embrace a simple life or pursue his destiny and become the Grinder he was meant to be.
Dean is encouraged by his therapist to dump his Grinder persona and discover the real Dean, and through therapy exercises, he begins to get those around him to come to grips with their own issues, which really gets under Stewart's skin.
An overly dramatic Dean scares off an important prospective client, which prompts Stewart to suggest that it's time to dump his "Grinder" persona and take a reality check by going to see a therapist. But after therapy, Dean overcompensates and starts "therapizing" the entire family, including Debbie, who considers quitting her difficult job.
Dean's TV Grinder replacement returns to Boise and Stewart invites him to hang out at the firm, where the two actors' rivalry resumes. Later, when Dean and Stewart argue over who's the better attorney, the brothers square off in a mock trial.
After a falling out, Dean and Stewart square off against each other in a divorce case. Meanwhile, life without Uncle Dean around the house has an impact on Ethan and Lizzie, which Stewart and Deb quickly notice.
Stewart and Deb inform Dean that his time with them is up and he needs to find another place to live. Meanwhile, a rival firm wants Dean to come work for them; and Deb's come to depend on Dean's former stand-in, who has been staying with the family.
Dean spots Timothy Olyphant (as himself) romancing Claire, and feels justified in trying to "win her back" by taking the lead on a case involving her friend, but he resorts to questionable tactics. Meanwhile, Stewart is thrilled to be the subject of a reporter's feature story, but isn't so excited after Dean steps in and turns the focus on himself.
Dean is asked to film a spinoff of his "The Grinder" TV series that will provide closure for his popular role, but Dean has problems dealing with being replaced by his character's TV brother. Meanwhile, Dean's real brother, Stewart, is excited for the opportunity to get Dean back into acting.
Dean is excited to spend a real Thanksgiving celebration with the family, but his meddling uncovers a major, surprising family secret. Meanwhile, flashbacks reveal events that led to Dean's departure from his hit TV drama and the show's subsequent cancellation.
Stewart tells Dean that to be considered a "regular guy," he needs to stop relying on his famous reputation, but Stewart has a change of heart when they wind up in trouble and Dean's celebrity may be their only way out. Meanwhile, Debbie hires a new assistant, who needs more assistance from Debbie to do her job.
Instead of following in his father's footsteps and joining the backstage technical crew, Ethan auditions for a role in the school play. Meanwhile, Stewart questions his father about why he gave Dean and him two different takes on how to live their lives.
Dean, frustrated at not finding love, has his belief in romance restored when he reconnects with a former girlfriend. Meanwhile, Deb tries to convince uptight Stewart to allow Lizzie to go on a supervised date.
Dean thinks that Claire doesn't show any interest in him because she's a mole and tells Stewart that she's been leaking company secrets to a rival firm. Meanwhile, Debbie and Stewart try to discover who fiddled with their DVR.
After a smash victory in court, the firm is flooded with business, and Dean wants to take on a big case, while Stewart disagrees, which puts the brothers at loggerheads. Meanwhile, Dean encourages Debbie to aggressively go for a promotion at work, but her plan backfires.