Speak No Evil stars Mackenzie Davis (Terminator: Dark Fate) and SAG award-winner Scoot McNairy (Argo) as American couple Louise and Ben Dalton, who, along with their 11-year-old daughter Agnes, accept the weekend-holiday invitation of Paddy (McAvoy), his wife Ciara (Game of Thrones) and their furtive, mute son Ant (Dan Hough).