Fifth Planet Gambit
The Fifth Planet Gambit was a name later given to the Time Lord expedition that intended to break Planet 5 from its time loop and utilize the Fendahl against the Enemy (PROSE: The Taking of Planet 5, The Book of the Enemy).
Unbeknownst to the Time Lords, the expedition was manipulated by the hermit so that the Fendahl Predator could be released and set on the Celestis. (PROSE: The Taking of Planet 5)
While this mission indirectly caused the destruction of Mictlan, therefore removing the Celestis' influence from the War, (PROSE: The Taking of Planet 5, The Book of the War) the Fifth Planet Gambit was ultimately designated a failure on the Homeworld (PROSE: The Book of the Enemy)