Gerry is forced to sub at a tough inner-city school after losing his job at Xavier Academy. Back at Xavier, the staff is worried that Robert is having a nervous breakdown because he didn't get the principal's job.
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.