In interviews about Knives Out (2019) and Glass Onion: A Knives Out Mystery (2022), writer/director Rian Johnson name-checks Agatha Christie, whose classic whodunits have spawned a century of high-profile adaptations. Since most are period pieces—see Kenneth Branagh’s Murder on the Orient Express from 2017 and Death on the Nile from this past year—there was room to stake out fresh terrain.