Caught in the middle of a messy divorce, five year old Phillip Boyle has taken to hiding inside blanket forts as he divides his time between Malcolm and Jessica Boyle, two parents who can’t stand the sight of each other.
While staying the weekend at his father’s run down colonial villa, they decide to build the biggest blanket fort ever, which soon turns into a sprawling maze that spans the house.
Eventually, Phillip's Mother arrives to pick him up, and a heated discussion quickly turns into an argument between her and his father. Philip quietly slips away and disappears unnoticed into the depths of the fort. Initially unconcerned, Malcolm and Jessica search for him through the tunnels, but they eventually realise that they have traveled far beyond the boundaries of Malcolm’s small house. They turn back, but find that the maze has changed, trapping them inside.
As they navigate the labyrinth over the next few terrifying hours, several things become apparent. Firstly, they cannot escape, as the seemingly thin blanket walls suddenly become barriers, impenetrable and seemingly alive. Secondly, each new area of the fort contains a challenge that they must overcome if they are to find their son, which increase in deadliness as they progress. Thirdly, they are not alone in the tunnels...
Now, the two parents must work together to discover the secret of the surreal and claustrophobic blanket fort, it’s connection to Malcolm’s house, and why it seems to want them dead...