Doctor Who: A Town Called Mercy

Doctor Who continues on UK, US and Canadian TV screens tonight, with A Town Called Mercy by Toby Whithouse.

The Doctor gets a Stetson (and a gun!), and finds himself the reluctant Sheriff of a Western town under siege by a relentless cyborg, who goes by the name of the Gunslinger.

But who is he and what does he want? The answer seems to lie with the mysterious Kahler-Jex, an alien doctor (yes another one!) whose initial appearance is hiding a dark secret.

Writer - Toby Whithouse
Executive producers - Steven Moffat and Caroline Skinner
Producer - Marcus Wilson
Director - Saul Metzstein

• UK: tonight, 7.35pm on BBC One and BBC One HD
• US: tonight, 9.00pm ET on BBC America
• Canada: tonight, 9.00pm ET on Space