Part conspiracy thriller, part comic horror, Steven Moffat's modern take on the Robert Louis Stevenson classic takes the ultimate tale of inner conflict to unforgettable new heights. It is 2007 and there's a new Dr Jekyll, with an old problem -- Mr Hyde. But the pair have a deal -- a body share -- and an impossible life is somehow lived. What Hyde doesn't know is that Jekyll is married. There's a wife and two children he'll do anything to protect from his dark side. With all the resources of modern technology, and the best surveillance hardware, Jekyll is determined to keep his dangerous alter ego in check by doing a deal -- with his own devil. What neither of them know is that an ancient organisation, with limitless wealth and power, is monitoring their every move, and a plan over a century in the making is coming to fruition. The return of Dr Jekyll is no accident . . .