The Tardis lands on the home world of the Sumaran civilization. The Doctor did not set the co-ordinates for the landing and discovers that Tegan did. He starts questioning if the Mara is still active inside of her from their previous adventure on the Kinda world.

Possessed Tegan and Lon try to find the location of the Great Crystal. The Doctor finds himself in prison with only Nyssa to get him out while Chela tells the Doctor about Dojjen and gives him Dojjen's journal.