Maia Marten is a highly accomplished lawyer in London whose ordinary morning run suddenly turns into a terrifying nightmare when she receives a call informing her that her young son has been kidnapped. Desperate to bring him home safely, Maia is forced to follow a series of cruel and dangerous instructions while continuing to run through the city. With no one she can fully trust and every passing second increasing the danger, she must push herself beyond her limits and make impossible choices. As the pressure grows, Maia discovers just how far she is willing to go to protect the child she loves.