It is 1947. Our dear friend, Detective Hercule Poirot (Kenneth Branagh), would rather live a quiet life in Venice, tending to his garden and only allowing access to the pastry delivery gondolier. A bodyguard named Vitale ('John Wick 2's' Riccardo Scarmarcio) imposes the cordon sanitaire. Yet mystery author Ariadne Oliver (Tina Fey) slips through and eventually makes that offer Hercule can't resist.

She invites him to a gathering on Halloween night at the residence of opera singer Rowena Drake (Yellowstone's Kelly Reilly, aka 'Beth Dutton'), which also happens to be a supposedly haunted palazzo. To cap the evening, a famous 'spiritista' played by Michelle Yeoh shall conduct a séance and perhaps uncover the truth behind the death of Rowena's daughter, Alicia.