Doctor: Peter Capaldi (Twelfth Doctor)
Companion: Jenna Coleman (Clara Oswald)
Maisie Williams – Ashildr
Joivan Wade – Rigsy
Naomi Ackie – Jen
Simon Manyonda – Kabel
Simon Paisley Day – Rump
Letitia Wright – Anahson
Angela Clerkin – Alien Woman
Jenny Lee – Elderly Woman
Robin Soans – Chronolock Guy
Caroline Boulton – Habrian woman
Directed by Justin Molotnikov
Written by Sarah Dollard
Script editor David P Davis
Produced by Nikki Wilson
Executive producer(s) Steven Moffat
Incidental music composer Murray Gold
Series Series 9
Length 50 minutes
Originally broadcast 21 November 2015
Rigsy contacts the Doctor and Clara for help. He shows them a number tattoo on his neck, counting down, with no memory of how he got it nor events of the last day. They trace his movements to a trap street in London that houses a small group of alien exiles, using technology to mask themselves as humans. Their mayor is Ashildr/"Me" ("The Woman Who Lived"), who warns them about breaking a frail truce that keeps peace on the street.
Me explains that they had sentenced Rigsy to death after he was accused of murdering Anah, a two-face Janus. They gave him the Chronolock tattoo which will when it reaches zero will summon a Quantum Shade, a being that takes the form of a raven, to kill him, a method they find humane. However, they also had to give Rigsy a dose of Retcon to forget the trap street's existence. Me allows the Doctor and Clara to prove Rigsy's innocence. Clara learns that the Chronolock can be transferred to another willingly. Believing Me will not let her die, Clara takes Rigsy's Chronolock without the Doctor's knowledge.
The trio meet Anah's daughter, Anahson, and learn her death was intentional. The Doctor demands Me take them to Anah's body, stored in a stasis chamber. The Doctor finds a recession in the controls that the TARDIS key would fit, and he proceeds to do so. However, the device clamps a metal ring around his wrist and takes the TARDIS key from him. The chamber opens to reveal Anah is still alive, and Me explains she needed a means to lure the Doctor here by implicating Rigsy. The band is a teleportation device to send the Doctor far away as to keep the truce, and she demands his Confessional Dial. Me then goes to remove the Chronolock from Rigsy only to discover Clara had taken it; Clara broke the contract Me had made with the Shade and she cannot undo it. The Doctor becomes angry, but Clara calms him down, asking him not to be upset nor avenge her death. Clara says her goodbyes and then steps into the street to face the Shade before it kills her.
The Doctor warns Me that Clara's caution was for Me's protection. Me apologises for her actions, and then activates the band, sending the Doctor away. In the post-script, Rigsy paints a tribute to Clara on the side of the abandoned TARDIS.