Wolf Mountain (2018)

Psychotic stepsister, Elena Koshka, lures Tyler Nixon to go on a getaway with her to Wolf Mountain. She loves him in a way she should not, although he is married, and she is married, her attraction and love for him can no longer be denied. She must find a way to be with him, even if it means manipulating his wife to leave town in an elaborate hoax to seduce her stepbrother.