Peter Miller (Hugh Jackman) is recently married to his second wife, Beth (Vanessa Kirby), and raising their newborn son. Peter's ex-wife, Kate (Laura Dern), shows up and says their 17-year-old son Nicholas (Zen McGrath) is depressed and has dropped out of school. Although Peter barely knows Nicholas, he agrees to house him. Peter has a terrible relationship with his own father (Anthony Hopkins), who was cruel when he wasn't absent from Peter's life. Peter has moved on from his childhood trauma, and hopes to be a good father to Nicholas.
Peter remains aloof of the trauma his cheating on Kate with Beth has caused his son. Soon after finding out Nicholas has skipped school since his first day living with Peter and Beth, Nicholas attempts suicide and is placed in an in-patient treatment facility, which leaves Peter feeling guilty.
Peter and Kate bring Nicholas home a week later after feeling sympathetic to his pleas that he regrets the decisions that led to the facility. Once back home, Nicholas makes tea for his parents and happily talks about seeing a movie as a family. As he leaves to shower and his parents discuss how things seem better, Nicholas shoots himself. Peter fantasizes about what life would be like had Nicholas lived.
