The TARDIS crew must make fire for the early humans to stay alive. But once they do, they may not be allowed to leave!

Tegana finally makes his move to assassinate the Khan, giving the Doctor and his friends an opportunity to thwart his plans and regain the TARDIS.

Tlotoxl's machinations result in both Susan and Ian being arrested. With the TARDIS once again trapped inside the tomb, the travellers' only hope for escape lies with Autloc and Cameca.