Robert Festinger (In The Bedroom) is behind the script, which was inspired by a true story and developed at Ecosse Films. Keaton will star as Emily Walters, an American widow living on the edge of Hampstead Heath who, despite close friendships and a nice flat, can't help but worry that she is drifting through life without a plan. One day, while looking out across the grasslands and trees, she spots a ramshackle hut and its unkempt occupant, who appears to be having trouble with violent attackers. After calling the police and watching them arrive, she goes to check on the man.
Turns out Donald Horner (Gleeson) has lived quietly and peacefully on the edge of the Heath for nearly two decades, but is now facing trouble from property developers who are trying to force him out. Emily decides to fight his corner, going up against her friend Fiona, who has taken the side of the developers.
Hopkins will be filming early next year on location in Hampstead. Gleeson will next show up in Ron Howard's (Rush) In The Heart Of The Sea, out 26 December, has Free State Of Jones going through the editing process and is currently shooting a role in Justin Kurzel's (The Snowtown Murders) Assassin's Creed. Keaton is at work on miniseries The Young Pope and has family comedy Christmas With The Coopers due 4 December. She will also voice Dory's mother Jenny in Pixar Animation Studios' Finding Dory, which swims in on 29 July next year.