DVD & Blu-ray review: Blood (15) "It's going to be a black hole, this one," intones Mark Strong's contemplative copper in this bleak police drama, set on the Wirral coast. He's investigating the murder of a 12-year-old girl, while two brothers, both detectives (Paul Bettany and Stephen Graham), take their familial frustrations out on the chief suspect. The cast act their socks off in this atmospheric, but flawed film.