As a serial killer stalks the city, Julia — a young actress who just moved to town with her husband — notices a mysterious stranger watching her from across the street.

Although its story may lack surprises, Watcher benefits from director Chloe Okuno's chilling grip on the material -- and Maika Monroe's terrific work in the leading role.

While it's a little formulaic and it takes its time to get going, Watcher has slow-building suspense and an ending that packs a punch.