Therefore, its known narrative elements are not a part of the Doctor Who universe as we, on this Wiki, choose to define it. It may have been the basis for a similar story in another medium, however — and that story may indeed be valid.
Tomb of the Cybs was a story concept in John Leekley's series bible for Amblin Entertainment's proposed 1990s Doctor Who television show. The story was based on the Second Doctor serial The Tomb of the Cybermen.
The Tardis arrives in the future on Telos. A human expedition is excavating the rumoured tomb of the last Cybs following the environmental destruction of their planet Mondas. But when the Doctor arrives, his half-brother the Master raises the temperature, reviving the Cybs.
- In an earlier draft of the concept, written 21 March 1994, Leekley elaborates that the explorers escaped from the tomb but were pursued by Cybermats, and the Doctor saved the day by lowering the temperatures again.