When a cold open starts with the Doctor breaking the fourth wall and delivering a causal loop monologue, and ends with him jamming to his own theme music, you just know you're in for a treat. After last week's more linear story, tonight's offering deviated from the template in just about every way imaginable. It moved location, introduced a new villain, separated the Doctor and Clara, turned up the timey-wimey to ten, yet the result was exactly the same—another top class outing from the man touted by many as Moffat's natural successor.
