The BBC Media Centre have released an official synopsis for episode three of Series 8, titled Robot of Sherwood, which you can check out below:
In a sun-dappled Sherwood forest, the Doctor discovers an evil plan from beyond the stars and strikes up an unlikely alliance with Robin Hood.
With all of Nottingham at stake, the Doctor must decide who is real and who is fake. Can impossible heroes really exist?
Robot of Sherwood airs Saturday 6th September on BBC One, with the broadcast time to be confirmed.