Bill Potts and her student friends are invited to move into a large house by a stranger played by David Suchet. The Doctor helps Bill to move house and afterwards refuses to leave. Bill Potts pretends The Doctor is her grandfather. Over the course of the episode, Bill's fellow student friends disappear.
The Doctor investigates and discovers that other students that have stayed in the house have disappeared over time, every twenty years. The occupants are being pulled into the woodwork and there is strange beetle like creatures that seem to be devouring the students.
The Doctor discovers the truth, in the top room of the building is Eliza, a woman made of wood. The landlord is renting the place out to students as food for the beetles which is keeping Eliza alive. It turns out the landlord is actually Eliza's child not her father. The Doctor persuades Eliza to release Bill's friends from where they are being held so that they can escape. The house crumbles and the students are left homeless.
The Doctor and Nardole are sent discussing what is behind the vault in the Doctor's earth home. The Doctor enters the vault with some food.