Dennis is a former Bosseigh High classmate of Shawn and Gus's, graduating alongside them as part of the Class of '95. Shawn joins him and his friends Earlie and Neil in the hallway at their 13-year class reunion.
When Shawn notices Howie Tolkin's case has been vandalized and asks whether they'd seen anyone tamper with it, Dennis mocks the idea of building a "shrine" for Howie just because he can throw a football ("Who cares?").
Dennis is later seen in the crowd when Shawn reveals that Howie and Eileen Mazwell murdered Peter Colter together.
