Ismene

Ismene was a non-canonical character who was created for the film adaptation of Problem at Sea in Season 1 of ITV's Agatha Christie's Poirot. Ismene was a young girl who was passenger on board the cruise ship, travelling with her aunts Nelly and Emily Morgan. Towards the end of the episode, Poirot borrowed her doll in order to act out his denouement of the murderer of Adeline Clapperton. Ismene also hid behind a curtain and called out some words on cue, making it appear that the doll could speak.

Ismene was played by Louisa Janes. There is no such character in the original story. There, the voice of the doll was provided by a unnamed stewardess with a voice like Mrs Clapperton. The source of the doll was not stated.