In Pacific Rim, huge alien monsters called Kaijus emerge from an interdimensional portal called “The Breach” at the bottom of the Pacific Ocean.
Over the course of three years, the Kaiju wreak havoc upon coastal cities along the Ring of Fire, such as San Francisco, San José del Cabo, Sydney, Manila and Hong Kong.
Humanity responds by constructing massive robotic machines called Jaegers, to combat the alien threat.
Each Jaeger is piloted by two or more people, who are connected by a neural bridge in a process called “drifting” to share the mental stress of piloting the machine.
In 2020, Gipsy Danger, piloted by brothers Raleigh and Yancy Beckett, defends Anchorage from a Kaiju codenamed Knifehead.
They both engage in combat, with Gipsy gaining the upper hand and defeating the Kaiju.
Unbeknownst to them, the Kaiju is still alive. The Kaiju ambushes them, critically damages Gipsy and throws Yancy out of the cockpit, killing him.
Raleigh manages to pilot Gipsy alone.
He then activates the remaining plasma cannon, killing Knifehead.
Traumatised by Yancy’s death, Raleigh quits the Jaeger Program. In 2025, the world governments decide to end funding for the continuous construction of Jaegers, in favor of building massive coastal walls, as the Kaijus are growing more powerful, their attacks more frequent and Jaegers are being destroyed faster than they are built.
The remaining Jaegers are relocated to Hong Kong under the command of Marshal Stacker Pentecost, who plans to destroy The Breach using a nuclear weapon.
Pentecost tracks down Raleigh at a wall construction site to persuade him to rejoin the program.
Traveling to the Hong Kong base, the Shatterdome, Raleigh is introduced to Mako Mori, director of the Jaeger restoration program and Pentecost’s adoptive daughter.
Four Jaegers remain in operation – the refurbished Gipsy Danger, the Russian Cherno Alpha, the Chinese Crimson Typhoon, and the Australian Striker Eureka that will carry the bomb, and piloted by father and son Herc and Chuck Hansen.