Krogh reveals that a Dr Polezig was killed the day before and frees the Doctor to assist his murder investigation while his companions remain imprisoned. Searching Verdeghast's chamber, the Doctor learns that Verdeghast's research is missing and that he was not killed by a living being. Dr Kravaal, a horribly scarred geneticist with an eyepatch, comes looking for Verdeghast and they send him away. Then Dr Sovak enters, crying for help. His neck bears the marks of an attacker like the one who killed Verdeghast. They leave Sovak to report to Director Rukh and find him in his office being strangled by a Cyberman with one human arm.