One Of Us Members of a family begin dying one by one at a funeral, while Youngest searches for the stranger in their midst. Details Casts Title One Of Us Release Date Runtime 01 Hours 49 Minutes Genres Horror Mystery Production Companies Northern Ireland Screen Production Countries Kit Connor... Youngest... Callum Woodhouse... ... Siobhan Fallon Hogan... ... Ian Beattie... ... Charlotte Hope... ... Douglas Henshall... ... Sienna Guillory... ... David Horovitch... Grandfather... Helena Bereen... Grandmother... Madison Stock... Youngest Cousin... Beccy Henderson... Cousin...