In 2006, NASA sends a signal to the exoplanet Gliese 581 g, where life is supposedly possible. In response, the intelligent inhabitants of the planet - the Regents - send five ships to Earth. Upon arrival in 2012, one of the ships crashes into a satellite, causing destruction on Earth. The remaining ships splash down near the Hawaiian Islands, where naval exercises are taking place. The aliens create a force dome to protect their ships and prevent interference. A large-scale battle begins between earthly destroyers and aliens. Despite their losses, Lt. Alex Hopper and his crew use the old battleship Missouri to defeat the aliens and destroy their mothership.