Sir Steve McQueen’s “Blitz” follows the epic journey of George (Elliott Heffernan), a 9-year-old boy in World War II London whose mother Rita (Saoirse Ronan) sends him to safety in the English countryside. George, defiant and determined to return home to his mom and his grandfather Gerald (Paul Weller) in East London, embarks on an adventure, only to find himself in immense peril, while a distraught Rita searches for her missing son.