Jeremy and Celia return a week early from their unsuccessful honeymoon to find that both Jeremy's partners have accepted his offer to stay in his house while he is away. The only problem is that they have each brought the other's wife with them.

Jeremy discovers one illicit couple, Celia the other. Both issue invitations to them for dinner. Complications pile up thick and fast as, realizing their dilemma and desperate to make a good impression on Jeremy's colleagues, the couple stages two dinner parties simultaneously, one on the patio and one in the dining room.

As if there aren't problems enough, Sid the plumber, up to his eyeballs in water in the cellar, has to call in the Water Board Emergency Service just when all seems resolved and Jeremy and Celia are attempting to salvage their lost honeymoon.