Raif Moyle (Rufus Hound) has been chosen to be the best man at his brother Tim's (Robert Webb) wedding to Saskia (Lucy Punch). Raif decides to give the couple an unforgettable gift in the form of a wedding video. He discovers that Tim has left his bohemian life behind and is marrying into a family aspirant of a higher-class lifestyle – especially Saskia's hideous grandmother (Miriam Margolyes).
Michelle Gomez is Jenna, the neurotic wedding planner whom it is revealed worked as an air hostess until she started to scream during turbulence. Jenna has novel and elaborate ideas for the big day but her reliance on tranquilisers and alcohol to steady her nerves leads her to behave erratically at the wedding.