The BBC Media Centre has released the official synopsis for the first episode of the new series of Doctor Who, read on for further details:
DEEP BREATH - by Steven Moffat
When the Doctor arrives in Victorian London, he finds a dinosaur rampant in the Thames and a spate of deadly spontaneous combustions. Who is the new Doctor and will Clara’s friendship survive as they embark on a terrifying mission into the heart of an alien conspiracy? The Doctor has changed. It’s time you knew him.
Doctor Who: Deep Breath will broadcast on Saturday 23rd August at 7:50pm GMT on BBC One and BBC One HD and will simulcast on TV and selected cinemas around the world.