Pacific Rim is the next Guillermo del Toro creation; it is an upcoming science fiction movie about alien monsters that discover the existence of humans and rise from deep within the Earth threatening to extinguish human life. Scientists and government officials explain this emergence of aliens from within the Earth by concluding that there is a portal between dimensions in the Pacific Ocean. Whatever the reason, this emergence provides a threat to human existence that the government tries to subdue by starting a war. To their disappointment, the war causes millions of people to die and consumes a large portion of the Earth's available resources.
The government trains soldiers to pilot giant robots to defend against the invading aliens. The pilots battle the aliens at the Pacific Rim, which is a series of volcanic islands in the Pacific Ocean where Earth's tectonic plates meet at the crust's edge and new lava rises out of the open Earth to form fresh land. The government developed the robots called Jaegers to be simultaneously controlled by two pilots whose brainpower is linked by connecting their minds in a neural bridge. As the first version of Jaegers prove to be too weak to subdue the aliens, new, more powerful versions of Jaegers are built; but version after version of remodeled and enhanced Jaegers prove too weak to defend against the alien eruption.
The human race's last hope for survival from an all-annihilating apocalypse comes from a former pilot and an untested trainee who team up and drive a legendary but outdated early trial Jaeger into the Pacific Ocean in what they think could be a final attack against the aliens and an end to the war.