Sapphire and Steel
"All irregularities will be handled by the forces controlling each dimension. Transuranic heavy elements may not be used where there is Life. Medium atomic weights are available -- Gold, Lead, Copper, Jet, Diamond, Radium, Sapphire, Silver, and Steel. -- Sapphire and Steel have been assigned......."
Sapphire & Steel was an intriguing science fantasy TV series produced by ATV between 1979 and 1982. It starred Joanna Lumley and David McCallum as the eponymous duo, Sapphire and Steel. Part of the fascination was that the introductory speech, above, was practically all the explanation we were given about who Sapphire and Steel were -- or whether they were even human. Their purpose, inasmuch as we could deduce, was to turn up where and when there was a rip or instability in space-time, and restore the balance, putting everything back where it was meant to be -- as much as they could, anyway.