When his flight is delayed coming home from a business trip, Keith Mitchell has to leave his daughter Alexis, who’s stuck at home under house arrest, alone for the night. Once Keith is finally in the air with full bars of WiFi, he notices a stranger enter the house on his security system. Unable to warn Alexis when the WiFi suddenly cuts out, Keith sits helpless from 30,000 feet in the air while his daughter fights for her life.
He Knows You're Alone is a 1980 American psychological slasher film directed by Armand Mastroianni, written by Scott Parker and starring Caitlin O'Heaney, Don Scardino, Elizabeth Kemp, Tom Rolfing, and Tom Hanks in his film debut. The plot follows a woman who is stalked by a killer targeting soon-to-be brides the weekend before her wedding.