Doctor Who, episode 3: A Town Called Mercy, review A Town Called Mercy was another Ronseal episode title this week, as the series returned to the American wild west for the first time since the 1966 William Hartnell story The Gunfighters. The story left virtually no cliché of the genre alone; visually, thematically or even musically. Even so, all this was effectively window-dressing for Toby Whithouse's powerful morality tale, where not everything was quite as it seemed and went on to explore issues of morality, ethics, conscience and justice in an absorbing fashion. At its heart was the dialogue between The Doctor (Matt Smith) and Adrian Scarborough's well-brought-to-life Kahler-Jex, a man forced by the necessity of war to do unspeakable things and now paying the price, mentally and physically. After The Doctor had acted as an effective executioner last week, it was interesting to see him behave in the same manner again - only to have Amy act as his conscience this time round with a well-crafted scene between the two. Indeed this was probably the only scene which gave companion Amy Pond (Karen Gillan) something to do other than stand around being a passive observer. Otherwise the episode could have been pretty much the same had she and husband Rory (Arthur Darvill) not been there, which was something of a waste of Gillan and Darvill's talents. After an initial larkiness Matt Smith gave one of his more restrained and authoritative performances, which suited the tone and gave the scenes between him and Jex added power. If The Doctor appears to be taking things seriously then it makes it easier for the audience to do likewise, something the programme has sometimes failed to do. Indeed, The Gunfighters suffered from being overly comedic, but that was definitely not the case here. Instead, what we had was an absorbing, thoughtful, adult piece of drama which, by not painting everything in black and white but utilising shades of grey, gave the viewer plenty to think about.