The TARDIS arrives on the planet Telos, where an Earth archaeological expedition led by Professor Parry is trying to uncover the lost tombs of the Cybermen. With a lot of help from the Doctor, the archaeologists enter the tombs. There, one of the party, Klieg, reveals himself and his business partner, Kaftan, to be planning to revive the Cybermen. After fending off an attack by Cybermats — small but dangerous cybernetic creatures — the Doctor destroys the Controller, defeats the revived Cybermen and reseals the tombs.