CUCKOO - Official Trailer

Reluctantly, 17-year-old Gretchen leaves her American home
to live with her father, who has just moved into a resort in the
German Alps with his new family. Arriving at their future residence, they are greeted by Mr. König, her father's boss,
who takes an inexplicable interest in Gretchen's mute
half-sister Alma. Something doesn't seem right in this
tranquil vacation paradise. Gretchen is plagued by strange
noises and bloody visions until she discovers a shocking secret
that also concerns her own family.

A Film by Tilman Singer
Starring Hunter Schafer, Dan Stevens, Jessica Henwick