In this Episode the thirteenth Doctor encounters a mysterious women namend Ruth Clayton which turns out to be a previous unknown incarnation of the Doctor. The Juddon, a intergalactic Policeforce, are hunting Ruth, Meanwhile the Doctors trys to get to know her Past.

The Thirteenth Doctor encounters shocking truths about her past. For Example that the unknown Incarnation, which she encountert previously, is a Doctor before the First Doctor. But all the memories of that Incarnation were wiped. In the Matrix on Gallifrey the Doctor gets to see this Incarnation which came from her subconcious.

In this Episode the thirteenth Doctor trys to rescue Yaz, Dan and Vinder by jumping in the Time Storm in which she is transported to her own past and gets to be her mysterious forgotten Incarnation and taking her place in this story.

With the 100th Anniversary of the BBC the era of the thirteenth Doctor (Jodie Whittaker) comes to an end. The thirteenth Doctor sees mental manifestations of her previous Incarnations like the first (David Bradley), fifth (Peter Davison), sixth (Colin Baker), seventh (Sylfester McCoy) and the eigth Doctor (Paul McGann).

In dieser Folge wird der Doctor in eine illusionäre Realität gezogen, in der er mit Belinda und ihrer mysteriösen Tochter Poppy lebt, während im Hintergrund die Rani versucht, den uralten Time Lord Omega aus dem Unterverse zurückzuholen. Als alles verloren scheint und der Doctor eine letzte Entscheidung allein treffen muss, erscheint plötzlich seine frühere Gestalt – der dreizehnte Doctor – um ihm ein letztes Mal beizustehen.