15 years after a global apocalypse, mankind is on the verge of extinction. Civilisation no longer exists, food is scarce and most eke out a living by stealing and killing. One boy clings onto life in the desolate British countryside, where staying away from others has been key to his survival. But this self-imposed isolation comes to an abrupt end when he crosses paths with another group of survivors and faces an enemy far more savage than any of them could imagine.

Ryan is a struggling son dealing with a constant internal battle regarding the inevitable loss of his Mother, and Sunny is desperate to escape the suffocating life that is depicted for her by her overbearing parents due to her being on the Autism spectrum. Both characters (and subsequently estranged family members) find themselves car-sharing to a funeral in Scotland. They have 3 days to feel comfortable in each other's company while feeling comfortable in their own skin.