John (Jack Reynor) lives with his mother, Jean (Toni Collette), in a Dublin social housing suburb and ekes out a meager living as a taxi driver. Spending his days hanging out with his best friend, Shane (Will Poulter) and long nights driving, he returns home one morning to find his mother unconscious from an overdose. It is not the first time. Embarrassed and engulfed by a sense of helplessness, Jean violently rejects John's attempts to help. But when Jean is offered a final opportunity to recover by her counselor Jim (Michael Smiley), and with no savings or insurance, John is forced to offer his services to a criminal gang to help pay for his mother's costly rehabilitation program. John is subsequently faced with a life-changing task that may alter him and his family's lives forever.