Inspired by a true story, "Hampstead" follows American widow Emily Walters (Diane Keaton). Emily is living on the edge of the Heath, but can’t quite seem to focus on the things that need attention, like her lovely old apartment, her finances and even her son. One day while looking out across the Heath from her attic window, she spies a ramshackle hut, which appears to be inhabited by an unkempt man Donald (Brendan Gleeson). She witnesses him being attacked by a group of professional thugs. Shocked, she calls the police and watches, through her binoculars, as help arrives. The next day she ventures into the woods in search of the man. Donald has lived quietly and harmoniously on the edge of the Heath for 17 years but now his lifestyle is under threat – his home is the target of property developers who’ve started using heavy-handed tactics to remove him.