Series 1 and 2 are fairly straightforward sitcom fare, with very little in the way of story arcs or connecting episodes. Much of the comedic content is concentrated on Donald and Patsy continuing to learn about one another despite several years together. In the first episode, Donald discovers his wife has not told him the whole truth concerning her life before they married - specifically, how many previous sexual partners she has had. The last episode of the second series reveals that, despite appearances from their photograph album, Donald and Patsy are not actually married.
The third series focuses on an affair between Donald and his client Laurel (Liza Goddard), which unfortunately kicks off just after Patsy and Donald finally tie the knot, leading to their visiting a marriage guidance counsellor in the first episode of the fourth and final series. The counsellor, Tristan Beasley (Tony Slattery) falls in love with Patsy, and they'll embark on an affair, but Patsy, realising she won't feel the same way about Tristan, ends the relationship.
In the final moment of the series, Patsy runs to Donald's arms, apologising to him for what she has done - it is left up to the viewer to decide whether the couple's marriage is doomed or they may be able to rescue their relationship.