control device to take control of them. In the duplication chamber, Stien becomes confused: the Doctor has realised that Stien's conditioning is unstable and tries to reawaken his ability to think for himself. As the mind-copying sequence nears completion, Stien breaks his conditioning and stops the process, freeing the Doctor. The Doctor finds Turlough and Tegan, and they return to the TARDIS along with Stien and another. Rather than depart, the Doctor decides to destroy Davros. With Stien and Lt. Mercer he heads to the station lab, leaving Tegan and Turlough in the TARDIS, which he has programmed to return them to the warehouse. The Doctor confronts Davros in the lab, but loses his chance to kill him when Stien's conditioning re-asserts itself long enough to let Lytton's troops kill Mercer. Stien refuses to accompany the Doctor back to the time corridor and runs off into the station. Davros dispatches his Daleks to Earth. Anticipating resistance from the Daleks not loyal to him, Davros opens a capsule of the Movellan virus. Two Daleks enter with the intention of killing him but are killed by the virus. At the warehouse, Davros' Daleks battle those loyal to the Supreme Dalek. The Doctor returns through the time corridor, realising that the "unexploded bombs" discovered earlier contain the Movellan virus. He opens one and places it behind the Daleks, who start to die. Lytton has escaped and sees the Daleks' demise. He swaps his Dalek uniform for a policeman's and joins his two fellow "bobbies". Davros prepares to flee, but the Movellan virus apparently kills hm. The Supreme Dalek appears on the TARDIS scanner and threatens the Doctor, claiming that the Daleks have duplicates of prominent humans all over Earth. Meanwhile, Stien is trying to activate the self-destruct sequence. Just as he is about to finish, the Daleks enter and exterminate him, but he manages to complete the sequence and destroys both the station and the Dalek ship. The Doctor calls for them all to leave, but Tegan refuses, saying she no longer enjoys her adventures, and runs off. The Doctor is saddened by this, and he and Turlough leave. As the TARDIS vanishes, Tegan runs back, remembering the Doctor's old admonition: "Brave heart, Tegan." She calls out to the empty air that she will miss him. Production The working titles of this story were The Return, Warhead, and The Resurrection. The story was