The BBC have released the official synopsis for episode 6, "The Caretaker", which will air on BBC 1 on Saturday 27 September 2014:
The terrifying Skovox Blitzer is ready to destroy all humanity - but worse, and any second now, Danny Pink and the Doctor are going to meet.
When terrifying events threaten Coal Hill school, the Doctor decides to go undercover.Steven Moffat wrote briefly about "The Caretaker" in his Radio Times episode guide:
"Clara has it all under control: her life at school, her life in space; her new boyfriend and her mad old Time Lord. Everything is humming along just fine, so long as everybody never actually meets. And then, one morning, just before assembly, Coal Hill welcomes a new relief caretaker with a Scottish accent."