The screenplay is inspired by Dame Agatha Christie's 1969 novel "Hallowe'en Party," with the setting changed from the UK to Venice, Italy. This is not the first time that Hallowe'en Party was adapted to film. In July of 2011, ITV Studios and WGBH released an 89-minute feature length film adaptation, Hallowe'en Party (2010), starring David Suchet as Poirot.
Hildur Guðnadóttir agreed to compose the film's score partly because her mother was an avid reader of Dame Agatha Christie.
Received little to no promotion from its ensemble given it was released during the SAG-AFTRA strike. Most films released during the strike could rely on the director for promotion, but that was not possible considering it's directed by star Sir Kenneth Branagh.