Gorilla Grodd escapes from his Gorilla City prison through the aid of Hector Hammond. He tells his followers that a fragment of the meteorite that gave him and Hammond their intellects has been found and must be retrieved.
Solovar, the scientist responsible for Grodd's imprisonment, radios the Flash for help. Since the Flash is unavailable, the Justice League sends Hal Jordan.
The Bureau of Amplified Animals appoints Rex the Wonder Dog as Hal's assistant in the mission, since he once helped the Flash defeat Grodd.
While searching for Gorilla City, Hal and Rex discover the Flash in the jungles of Africa.