Poirot and Hastings are at Lake Windermere for an attempt on the world speed-boat record. Two sisters have premonitions of danger. Soon a rich elderly widow is hurt by falling down stairs, then later she is killed by poisoning with phosphorus. The "dumb witness" Poirot must fathom to solve the mystery is a dog.
Elenco: David Suchet , Hugh Fraser , Philip Jackson , Pauline Moran .