He may be crashing on to the big screen in a few weeks in Pacific Rim, but before he heads off to battle really big monsters Idris Elba has some dirty criminals to deal with. He returns to our TV screens tonight as maverick detective Luther, and it's not long before he's on the case of a twisted fetishist murdering women in a horrific echo of an unsolved case from the 1980s. And as if that wasn't enough, there's a second murder, a road accident, and a rather attractive lady to deal with too...