The Doctor and her companions arrive in Norway, landing nearing a cabin. Meeting its sole occupant, blind teen Hanne, they learn that she and her father Erik moved into the cabin following the death of her mother Trine, and that her father went missing four days ago. Hanne fears going out to search for him due to a creature she hears every day. Upstairs, they discover a bedroom mirror with no reflections that the Doctor reveals to be a portal. She, Graham and Yasmin enter it, while Ryan remains behind with Hanne. Shortly after their departure, Hanne knocks him out and follows them, forcing Ryan to do the same. Through the portal, the Doctor and the others find themselves in the Anti-Zone, a buffer-space between universes to prevent catastrophic damage.
Within this universe, the Doctor encounters Ribbons of the Seven Stomachs, who offers his help for her screwdriver, but is eaten by Flesh Moths when he makes a grab for it. The others quickly escape them by entering another portal. They find themselves arriving in a cabin within a parallel universe, and encounter Erik talking with Trine, despite knowing she is dead. During this time, Graham encounters Grace, despite the circumstances of her death, and both he and Erik experience a difficult conversation about their loss. The Doctor quickly deduces a sentient universe incompatible and exiled from the real one, which seeks companionship and has now cut them off from their universe. When Hanne arrives and recognises Trine is not real, the Doctor convinces the Solitract to let them go, knowing their presence threatens to collapse it.
When Erik refuses to leave, the Doctor offers to take his place and give the Solitract her broad experience from travelling the universe. Erik is ejected in agreement, leaving the Doctor in a white space along with a talking frog, a form the Solitract finds delightful. Despite being fascinated with interacting with it, she explains she can’t stay and urges the Solitract to remain interesting. She then makes her way back through the Anti-Zone before the portal to the universe collapses. In the aftermath of their adventure, Erik decides to return to Oslo with Hanne, while Ryan takes interest in Graham’s conversation with Grace and bonds with him.
Directed by Jamie Childs
Written by Ed Hime
Script editor Nina Metivier
Jodie Whittaker (Thirteenth Doctor)
Bradley Walsh (Graham O’Brien)
Tosin Cole (Ryan Sinclair)
Mandip Gill (Yasmin Khan)
Sharon D Clarke – Grace O’Brien
Eleanor Wallwork – Hanne
Kevin Eldon – Ribbons
Christian Rubeck – Erik
Lisa Stokke – Trine