Saving the World/Sandbox

While villains love to go about causing The End of the World as We Know It, the Heroes are most likely motivated by the polar opposite, Saving The World. A fairly simple plot/motivation related to For Great Justice and what not, this trope is pretty broad and very common for many stories not focused on character interaction only.

Most of the time, this is the result of The Call, or occasionally may be someone who Jumped At the Call and is just trying to be able to do this. Note, this doesn't always happen and it's entirely possible for the bad guy to win and the Earth to be destroyed. Sometimes, the villain will actually help with this goal, what's the point in taking over a pile of rubble after all? (Especially if it's Not Me This Time.)

Extremely common in some genres, such as High Fantasy, soft Sci Fi, and The Epic, as noted on Old!SavingTheWorld.