Arriving in present-day Norway, The Doctor and the Companions find a boarded-up cottage in the isolation of the fjords and a blind girl named Hanne whose father has been missing for four days. She believes the monster in the woods that hunts every day at the same time must have come and taken her father. Her mother died and, in his grief, her father moved them to this cottage and away from Oslo where they had lived. While waiting for the monster, Graham discovers a mirror that doesn't reflect his image. The Doctor realizes that it is a portal and goes through with Yaz and Graham to investigate. They end up in a cave system with a creature named Ribbons who wants to trade for the sonic as well as eat them. The caves also have flesh moths that feed on living tissue. Ribbons gest eaten just before they find another portal which spits them out in an alternate world where they find Erik, Hanne's father, and her supposedly dead mother, Trine. Also, they discover Graham's dead wife, Grace, is there too. The Doctor and Yaz try to work out what is happening and The Doctor remembers the story of the Solitract, a conscious universe that is fundamentally incompatible with the real universe. When they confront Trine and Grace with this information, they are, one by one, thrown back through the portal. Erik is the final holdout and The Doctor offers herself as a better friend but her presence is still destabilizing the world and the Solitract sends her back as well. Graham is shaken by his encounter with Grace but Ryan consoles him and their bond grows.