This time, a Belgian detective solves a murder committed at a Halloween party. A 13-year-old girl was drowned during a youth party held on the eve of All Saints' Day. The famous writer Ariadne Oliver, who happened to be attending the fun, decides to approach Hercule Poirot - it does not seem to her that it could be a crime committed by a deranged criminal in the sense of passing. The key to the mysterious death probably lies in a sentence spoken by the murdered Joyce during the preparations for the party: I saw a murder...