(He turns to the door where the MASTER is still stood, his back to him.) DOCTOR: Mailer, why are you helping the Master? The BRIGADIER gets out.) The DOCTOR sighs.)
Plan: A: The Doctor; Q: Who is forced to help the Master control the mind parasite? A: Yates; Q: Who finds out where the Thunderbolt has been taken? A: the Master's men; Q: Who captures Yates? Summary: The Doctor is forced to help the Master control the mind parasite while Yates finds out where the Thunderbolt has been taken only to be captured by the Master's men.