Doctor Who Season 9 Episode 10

Have you ever found yourself in a street you've never seen before? The next day, could you not find that street again? You weren't dreaming. Your memory isn't playing tricks. Like many lost souls throughout the ages, you have stumbled on an extraordinary secret - be grateful you survived it. The Doctor and Clara, with their old friend Rigsy, find themselves in a secret alien world, folded away among the streets of London. Not all of them will get out alive. One of the three intruders must face the raven...