Unwillingly attending a diversity course Martin somehow achieves an inner peace and, to his surprise, beds the instructor, Sarah (Nicola Walker).
Much of the rest of the series revolves around their on-and-off relationship, her somewhat masochistic yearnings, and the highs and lows of his moods.
She augments her own meagre income by teaching courses in "life editing" and similar fads at adult education colleges, dragging Martin along to make up the numbers, but not to participate.
Ever present is the "Fifth Horseman of the Apocalypse, Embarrassment" who pays regular visits, especially when Martin lets himself be led into temptation, such as by scaling the tower at the local fire station, in the nude, with a couple of adventurous neighbours.
Like the hero of Married, Martin is a world-class curmudgeon who deconstructs the world around him in long literate sentences.