Dawn of the Planet of the Apes

In the aftermath of a "Simian flu" pandemic which decimates the earth's human population, the leader of an advanced ape colony in the muir woods helps an architect fix a hydro dam which puts san francisco back on the grid, but the fragile trust between man and ape is broken when a former lab ape "Assassinates" the leader and wages war against human survivors in the revitalized city.