For centuries, the disappearance of the Cybermen from the universe has been a mystery. The Doctor, Jamie and Victoria arrive on Telos - once the Cyber home world - just as an Earth expedition uncovers the entrance to a long-lost control center filled with baffling technology. With the Doctor's help, the archaeological party discovers the last of the Cybermen, frozen and entombed in a vast underground cavern. But by entering the tombs, the humans have sprung a fiendish trap. All around them, the Cybermen begin to rise from the dead.