Gerry and Simon are both assigned student teachers. Gerry is thrilled to have a minion picking up the slack, while Simon is anxious about the added responsibility. Gerry soon learns that his hands-off approach will not work, as his student teacher, Gloria, is terrified of the students and requires Gerry's presence at all times.
Based on Gerry Dee's real-life experiences as a high school teacher before he switched to comedy full-time, MR. D is a story about a charming, under-qualified teacher trying to fake his way through a teaching job, just like he often fakes his way through life. The premise shines the light on teaching from the teacher's point of view, and as it turns out, teachers don't know everything, especially Mr. D - who struggles to keep one step ahead of his students.