Single mother Diane (Anne Dorval) is careless, smoking, drinking, and swearing, and has a heart that never gives up. She raises her son Steve (Antoine-Olivier Pilon), who suffers from ADHD and often commits violent acts, and the relationship between mother and son is on the verge of exploding. Diane is worried that Steve will cause trouble, and Steve is eager to express his love for his mother. The new neighbor Kayla (Suzanne Clément) appears at the right time. This high school female teacher with aphasia acts as a buffer valve for mother and son, allowing all three people to begin to see balance and hope. However, the consequences of Steve's previous violent behavior are fermenting, and Diane needs to pay a large sum of compensation. She decided to sell her happiness and made a painful decision: to send her son back to the hospital for treatment... "Mummy" is the fifth feature film directed by the young Canadian director Xavier Dolan. It is in contrast to Dolan's debut "I Killed My Mother", which made a stunning debut in the Cannes Directors' Fortnight five years ago. It also tells the story of the manic yet profound, dependent yet alienated mother-son relationship in a single-parent family. But unlike the highly autobiographical nature of "I Killed My Mother", "Mummy" is more generous and warm, with fuller emotions. It can almost be regarded as Dolan's expression of guilt for his debut work. The film was shortlisted for the main competition unit of the 67th Cannes Film Festival and shared the Jury Award with "Goodbye Language".