In 2013, the Earth's cities are attacked by Kaiju, very large monsters who come from a portal on the floor of the Pacific Ocean. To battle them, the nations in the Pacific Rim build the Jaegars: very large robots piloted by two people whose brains are linked to the robots. This allows the pilots to control the robots using their mind, and the robots do the same actions that the pilots do. Although the Jaegars work well in killing the Kaiju, the attacks happen more often and are more powerful. By 2025, the governments of the Pacific Rim have ended the Jaegar project and build very large walls to protect humans from the Kaiju. Most of the film is set in this period, focusing on the war's later days.