11-year-old Thomas wants to keep up with his older siblings - until a tragic accident changes everything. Now unable to walk and feeling left behind, Thomas`s world shifts when he meets Fleak, a tiny, mischievous creature from another dimension. As their friendship blossoms, Fleak leads Thomas to a surreal world where he can walk again, by letting go of his own shadow. But freedom comes at a cost. Thomas`s abandoned shadow grows into a terrifying but goofy monster that threatens to destroy both Fleak`s world and his own. To stop it, Thomas must reconnect with the very people he felt so distant from - his siblings.