After defeating the Dominators and starting off a volcanic eruption, the Doctor, Jamie and Zoe find themselves and the TARDIS in the path of a lava flow. Upon trying to dematerialise out of the way, the TARDIS experiences a fault in the fluid link. At the insistence of Zoe and Jamie, the Doctor uses an emergency unit that takes the TARDIS into another dimension outside of reality. Upon their arrival into an empty white void, the travellers find themselves assaulted, first subtly then overtly, by an unseen force. The attack results in the TARDIS breaking apart and the travellers being scattered.