A child as a central protagonist unleashing horror is an oft-used device in the horror-supernatural genre. In writer-director Mike Flanagan’s Before I Wake, Jacob Tremblay plays eight-year-old Cody, a child who has had a troubled start in life. He is bounced from foster home to foster home, and his latest guardians are Jessie (Kate Bosworth) and Mark (Thomas Jane), who are dealing with the tragic loss of their young son, Sean (Antonio Romero).

Cody is a polite, sweet and cute little child, but he’s terrified of falling asleep. He clutches a shoebox tightly to himself when he first enters his new home. As the household goes to sleep that night, we discover that the box is full of stimulants to help Cody stay awake. When Cody does fall asleep, his foster parents finally understand why the child is glugging cans of cola, eating sugar and reading all night. He either dreams of beautiful things, even conjuring up Jessie and Mark’s dead son, or has frightening nightmares, which almost always feature a skeletal apparition Cody has dubbed the Canker Man.

At first, Jessie and Mark are awed and comforted when Cody’s imagination manifests Sean, but when they experience the true horror of his nightmares, Jessie decides to determine their genesis.

As long as Flanagan explores the layer of grief, healing (with parents who have lost their child and a child who has lost a parent) and the power of the mind, the film has possibilities, but with the manifestation of the Canker Man, who swallows the living whole, leaving no trace of them except a memory, this psychological thriller becomes absurd. Canker, it turns out, is Cody’s version of the word Cancer, the affliction that took away his mother. The story bypasses any explanation of disappearing children and adults, including that of Mark, a loss that Jessie recovers from rather well. Before I Wake uses old-school scares—shock, loud sounds in the dark, a ghastly creature and slow movements by the perpetually hurting Bosworth. Suspension of disbelief is the bedrock of this genre, but there are too many conveniences and not enough scares in the script for the suspense to remain for long.

Before I Wake released in theatres on Friday