Comrade (2006)

After discovering that his father has lied to him for years about his estranged sister and his mother, 14-year-old Ilan runs away from home and ends up living with his sister, Dalia, who works on a cruise ship and is having an affair with a married man. While Dalia is at work, Ilan explores her down-and-out neighborhood and discovers and befriends Avram, an elderly holdout Communist living in an abandoned building with his weapons cache and marijuana-growing business, biding his time for the ultimate battle against the capitalists.