Following the tunnel created by the Nitro-9 blast, the Doctor and Ace enter a chamber under the lake, finding a door programmed to open at the Doctor's voice. The Doctor tells Ace that "Merlin" may well be his future self. Presently, they realise that the chamber is part of an organic spaceship and find the body of King Arthur, lying next to a sword, which was apparently the source of the distress signal, and also lured Mordred and Morgaine. When Ace removes the sword from its plinth, she activates a defence mechanism, unleashing a hostile, glowing entity. Attempting to hide, Ace enters an alcove. A door closes, and the alcove starts to fill with water. As Ace yells for help, the entity knocks the Doctor unconscious.