When Gerry is suddenly promoted from sub to full-time teacher, his initial thrill is quickly squashed by the realization that he's back to real teaching responsibilities.
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.