Halloween is a crime investigation film based on the book of the same name by Agatha Christie, known for titles such as Murder on the Orient Express and Death on the Nile. In the third film in the Hercule Poirot (Kenneth Branagh) saga, the detective is back to investigate yet another mystery in the most beautiful city in the world: Venice. The man is invited by his friend, Ariadne Olivier (Tina Fey) to participate in a séance at Rowena Drake’s (Kelly Reilly) mansion, which is reputed to be haunted by the ghosts of children. At first, Poirot denies the invitation, but becomes curious to discover that the session will be conducted by the mysterious medium Mrs. Reynolds (Michelle Yeoh), and is intended to make contact with Rowena’s daughter, Alicia (Rowan Robinson), who committed suicide. – but the mother is convinced that the girl was killed by the local ghosts. On the night of the session, however, a crime causes the situation to take a macabre turn.