The Sky Behind the House (2011)

Jon's mom is dead, yet she still comes every night before he falls asleep to wish him a good night. But one night she does not, and Jon can't sleep. His dad comes up with an idea; he ties a long red thread around his big toe and leaves Jon the other end to hold on to while he sleeps. Now Jon can tug on the thread if he becomes frightened. Late in the night, Jon wakes with a start, following the thread, he finds that it doesn't lead to his father's bedroom, but down the hall, out the front door, and into what he fears the most; the darkness in the never ending forest behind the house.

Unfortunately the movie The Sky Behind the House is not yet available on HBO Max.