Ashildr was a girl that lived in a Viking village that was invaded by alien warriors called the Mire. During the battle, Ashildr was killed, but the Twelfth Doctor resurrected her and made her immortal thanks to Mire technology. Although, the Doctor tells Clara that immortality is a curse (The Five Doctors, The Lazarus Experiment). Ashildr/Me lived for centuries until she encountered the Doctor again in the Regency. In the present day, Clara and the Doctor found that Ashildr had become the Mayor of a hidden trap street, home to alien refugees. Ashildr had put a Chronolock on the neck of Clara’s friend Rigsy. Unfortunately, the Chronolock was passed onto Clara and she was killed by Ashildr’s Quantum Shade raven instead. Ashildr handed over the Doctor to her employers, the Time Lords. After the Doctor was captured and interrogated inside a confessional dial, Ashildr met the Doctor again at the end of the universe, where the two contemplated the nature of the Hybrid, the being that made the Doctor flee Gallifrey in the first place.

The Girl Who Died

★★☆☆☆

TX: 17/10/2015

Written by Jamie Mathieson & Steven Moffat    Directed by Ed Bazalgette

The Twelfth Doctor and Clara are captured and taken to a Viking village. The villagers are being attacked by a sophisticated warrior alien race called the Mire. The ruthless Mire are bio-mechanical lifeforms that wear heavy armour. The Doctor reads up on the Mire in his 2000-year diary (he previously had a 500-year diary in The Power of the Daleks). Clara and Ashildr are captured on a spacecraft with some of the other Vikings. The men are killed and drained of their adrenaline and testosterone, while Clara and Ashildr meet Odin, the leader of the Mire species. Before Clara can stop her, Ashildr declares war on the Mire, and Odin grants them 24 hours to prepare. The Doctor is faced with the impossible challenge of turning a village of harmless Viking civilians into a fighting force worthy of defeating the deadliest warrior race in the galaxy. As the situation looks increasingly bleak, the Doctor finally comes up with a plan. Electricity from electric eels is used to electromagnetically remove the Mire helmets, allowing the Doctor to steal one. The Doctor modifies this and makes Ashildr wear it, allowing her to envision an articulated puppet as a dragon, which is broadcast to the other Mire which scares them off. Odin vows to attack again, but the Doctor threatens to send embarrassing video footage of the rout captured by Clara’s phone to the universe unless they leave Earth. Odin and the Mire peacefully depart. The village celebrates its victory until they find out that Ashildr died from the helmet’s use. The Doctor is frustrated until he remembers why he took the form of Caecilius, who he saved in The Fires of Pompeii: to always save someone, no matter what. He “breaks the rules” and modifies two chips from the Mire’s helmets, one of which he implants in Ashildr, and the other he gives to her father for later use. The chip rapidly regenerates Ashildr’s body and she regains consciousness. As they leave, the Doctor tells Clara that he fears that he gave Ashildr a fate worse than death as the chip will effectively make her immortal and alone. He provided the second chip in the hope that she would give it to someone that she cares for. This adventure leads into the events of The Woman Who Lived.

The Woman Who Lived

★★★☆☆

TX: 24/10/2015

Written by Catherine Tregenna    Directed by Ed Bazalgette

The Twelfth Doctor arrives in Regency England where he prevents a highwayman robbery. ‘The Shadow’ highwayman turns out to be Ashildr, whom the Doctor and Clara met in the previous episode The Girl Who Died. Ashildr is now immortal due to the Mire technology given to her by the Doctor in order to revive her. Ashildr has become bitter, jaded and un-empathetic as a result of living for centuries. She now refers to herself as Me. Ashildr and the Doctor find an amulet of alien origin in a country manor. The manor is home to an alien lion called a Leonian. Leandro the Leonian and Ashildr plan to use the amulet to open a portal to the homeworld of the Leonians. Leandro and Ashildr put their plan into action at the public execution of the funny highwayman, Sam Swift the Quick. The Doctor arrives and saves Sam Swift from being hanged, but unfortunately Ashildr stabs the amulet into Sam which creates a beam of purple light that opens the portal. Lasers and other bombardment comes crashing down onto Earth from the Leonian homeworld. Realising that she has been betrayed by Leandro, Ashildr agrees to help the Doctor close the portal. The Doctor uses the second Mire medical tablet to resurrect Sam Swift and make him immortal too. The amulet on his chest disconnects and the portal closes. Leandro is killed by his own kind. The Doctor makes his goodbyes to Sam Swift and Ashildr, telling the latter that he will check in on her in the future, as he did with another immortal person, Captain Jack Harkness. The Doctor later sees a photo of Ashildr in the present day on Clara’s phone. Ashildr returns in Face the Raven and Hell Bent.

Face the Raven

★★★☆☆

TX: 21/11/2015

Written by Sarah Dollard   Directed by Justin Molotnikov

The Twelfth Doctor and Clara receive a phone call from their old friend Rigsy who they previously met in Flatline. Rigsy has discovered a Chronolock tattoo on his neck, a number that is counting down. The Doctor decides to fly the TARDIS above London to trace the person who planted it on Rigsy. The Doctor, Clara and Rigsy eventually find the entrance to a Trap Street, a refuge for alien refugees hidden behind a perception filter. The Mayor of the Trap Street is the immortal Ashildr, whom the Doctor and Clara previously met in The Girl Who Died and The Woman Who Lived. Ashildr has become ruthless and unmerciful over the centuries and is happy to condemn petty crimes like theft to a death sentence. Rigsy is accused of murder and so Ashildr put the Chronolock (a countdown to execution) on his neck and wiped his memory. In private, Clara stupidly asks Rigsy to pass the Chronolock onto her. However, when this is revealed to Ashildr she says that the Chronolock cannot be stopped. A tearful Clara says goodbye to the Doctor before she too is killed by the Quantum Shade raven, which flies into her. The enraged Doctor is handed over to Ashildr’s employers, who Ashildr refuses to name. Rigsy paints a mural of Clara on the TARDIS.

Hell Bent

★★☆☆☆

TX: 5/12/2015

Written by Steven Moffat      Directed by Rachel Talalay

The Twelfth Doctor finally returns to his restored childhood home of Gallifrey. He sends the corrupt Rassilon into exile before re-assuming the Presidency of the Time Lords. Despite warnings from the Sisterhood of Karn and the Time Lords, the Doctor attempts to rescue his deceased companion Clara Oswald. He uses a stolen Gallifreyan TARDIS to rescue Clara in her last second of life. The Doctor puts Clara into a time loop but he is forced to erase his memories of her. The Doctor later arrives in a diner, searching for someone who he cannot remember the name of. The mysterious waitress (Clara) listens to his story before leaving in the diner (a disguised TARDIS) with Ashildr/Me to have adventures of their own together. “Nothing’s sad until it’s over, and then everything is.”