The Affair at the Victory Ball

A costume ball is the perfect place to hide a murder, which is probably why the Victory Ball has one. Poirot and Hastings attend the festivities, and somewhere in the crowd of fancy dress a guest is stabbed to death. The Victory Ball is the kind of party where everyone is somebody else for the evening, which suits a murderer down to the ground. The only clue, to begin with, is a fragment of costume, which in a room where everyone is dressed as someone else is almost no clue at all. The next day the case gets stranger: a second figure from the ball dies of a drug overdose, and Poirot has to decide whether the two deaths are connected or just badly timed.

The guests come under the spotlight one by one: Viscount Cronshaw (Mark Crowdy), Eustace Beltaine (David Henry), Coco Courtenay (Haydn Gwynne), Chris Davidson (Nathaniel Parker) and Mrs Davidson (Natalie Slater) of the same family, Mrs Mallaby (Kate Harper). Everyone was in costume. The alibis all depend on a mask. Haydn Gwynne's Coco Courtenay is the sort of woman who knows everybody and trusts nobody, which makes her invaluable. Japp sorts through the official side while Poirot measures the gap between what people looked like and what they were doing.

Andrew Marshall wrote it with Agatha Christie, and Renny Rye directed. The ball scenes are properly lavish, all the more sinister for being so pretty. The period dresses and masks do half the storytelling, and the episode trusts them to do it.

There is a particular pleasure in murder mysteries that make you look at clothes. The fragment of costume is the whole story, and the episode knows it, teasing it out without ever cheating. The solution is tidy in the way Christie's solutions are: obvious once explained, invisible before. The overdose is the kind of loose end that could sink a lesser story, but here it tightens the knot instead. Hastings, watching Poirot work, looks the way we all feel.