Le Flux et le reflux (S10E03)

Hercule Poirot's famous powers of deduction are called on following the death of Richard Abernethie, head of the somewhat dysfunctional Abernethie clan. As the family gather for the reading of Richard's will, Abernethie's sister Cora blurts out her belief that he was murdered. Poirot assumes he is travelling by train across the country to interrogate Cora about her bombshell, but on the day after the funeral Cora herself is hacked to death by an intruder. The family's solicitor Entwhistle asks him to investigate not just Richard's death, but the mysterious demise just 24 hours after his cremation of his younger sister. (iTunes)