Arlington Grange marks the start of the annual fun run, but most of the runners are none too pleased with Mrs. Peacock's new fiancé, French Count Henri de Beauchamp.
The "Stop the disco action group" attempts to stop property developer Mr Hall from building a discotheque on the village pond. Unfortunately Colonel Mustard is delayed with a flat tire.
During one Mrs. Peacock's regular Bridge evenings, Professor Plum invites a pair of professional players, Mr. and Mrs. Hope to teach Elizabeth and Vivianne a lesson. But when the stakes grow too high, Plum begins to regret his decision.
Peregrine Talbot-Wheeler, host of TV's 'Antiques Treasure Trail' visits Arlington Grange to evaluate Mrs. Peacock's antiques and manages to tick off everyone presents before he starts.
Col. Mustard and Mr Chapman both want to succeed the recently deceased local MP's. Chapman especially rubs a lot of people the wrong way, starting at the funeral of the former MP.
Arlington's annual summer fête is held at Mrs. Peacock's estate, but it's special guest, commercial actor Bernard Kirkbride proves himself to be very unlikable and crass to everyone. But by some twist of fate it is not the actor but another guests who is murdered.
Richard Forrest, whose late father, a judge, previously owned Arlington Grange, returns to it for Christmas bearing deadly presents for and incriminating knowledge about all the other people present.
