"Nightmare in Silver" is the twelfth episode of the seventh series of Doctor Who, starring Matt Smith as The Eleventh Doctor, Jenna-Louise Coleman as Clara Oswald, and with a guest starring role by Warwick Davis. It was written by Neil Gaiman, who previously wrote The Doctor's Wife.
The episode involves the Cybermen, a perennial foe of the Doctor's. The Doctor, Clara and two children under her charge visit the universe's best amusement park, which is quickly revealed to be the hiding place for the last of the universe's Cybermen. The two children are taken hostage, and the Doctor must free them, even as his own mind and body are attempted to be converted by a Cyberleader. While Clara leads a ragtag group of misfits against the invincible cyberarmy, the Doctor has to play a very hammy game of chess against himself, all while hints about the season's arc are dropped right and left.
Being written by Neil Gaiman, this episode is an affectionate mix of tropes and motifs, both specific to Doctor Who and and general to fantasy. Overall, it has a romantic mood, with a bit of drama and even horror mixed in. Like many Doctor Who stories, it resolves on an ending that might not stand up to strict logical scrutiny, but that is still fulfilling. If there is a problem with this story, it is probably the problem with much of much of Doctor Who in this series: a plethora of ideas, characters, settings and plot twists, rushed through before they can sink in.