Battleship PLOT

In 2005, the distant Gliese planetary system is discovered to have a potentially habitable planet and a communications array is built by NASA in Hawaii to send a transmission to contact any intelligent life. Meanwhile, Alex Hopper is arrested while attempting to impress Sam Shane. His brother, naval officer Stone, forces Alex to join the U.S. Navy in order to improve his life.

In 2012, Alex and Sam are in a relationship and Alex serves as a lieutenant aboard USS John Paul Jones while Stone commands USS Sampson, but Alex is in danger of receiving a disciplinary discharge. During the 2012 RIMPAC exercise, five alien spacecraft arrive. Their communications ship collides with a satellite and crashes in Hong Kong while the other four land in the waters off Hawaii. Sampson, John Paul Jones, and their Japanese sister ship JDS Myōkō are ordered by Admiral Terrance Shane to investigate, and they subsequently discover a floating structure. When it is touched by Alex it generates a force field that encloses the Hawaiian Islands and separates the three ships from the fleet. Three alien warships surface and commence to engage both the Sampson and Myōkō which are destroyed, resulting in Stone's death, while the command crew of John Paul Jones are killed. With Alex assuming command as the ranking officer, they recover the survivors from Myōkō including its commanding officer, Captain Yugi Nagata. The aliens also launch drones to attack Hawaii which cause heavy damage.

On Oahu, Sam is accompanying retired U.S. Army Colonel and double amputee Mick Canales on a mountain hike. After becoming aware of the aliens' presence, they encounter scientist Cal Zapata who informs them the aliens have taken over the communications array, and Mick determines that they are planning to use it to re-establish military communications with their home planet. Aboard John Paul Jones, naval personnel capture a semi-conscious alien. The alien forms a telepathic link with Alex, showing him their history of destroying worlds. Other aliens arrive and retrieve their comrade, but are prevented from sabotaging the ship. Examination of the captured alien's helmet reveals the aliens are sensitive to sunlight. Ashore, Sam, Nick and Zapata recover his spectrum analyzer from the aliens and they use it to radio John Paul Jones to inform them the aliens intend military telecommunication with their own home planet in four hours.

Captain Nagata suggests to surreptitiously use National Oceanic and Atmospheric Administration's tsunami warning buoys around Hawaii to track the alien warships. This allows John Paul Jones to destroy two of them. At dawn, they lure the remaining warship eastwards as Alex and Nagata shoot out its bridge windows, blinding its crew and allowing John Paul Jones to destroy the alien ship. However, John Paul Jones is simultaneously sunk by alien drones.

The survivors return to Pearl Harbor and commandeer the previously decommissioned WWII battleship USS Missouri with the aid of the retired veterans preserving her, restoring her to battle readiness and confronting the alien structure, revealed to be a giant mothership. The Missouri severely damages the mothership and disables the force field, and Admiral Shane scrambles a flight of Royal Australian Air Force Boeing F/A-18 fighter jets from aircraft carrier USS Ronald Reagan. Meanwhile, Sam, Mick and Cal attempt to stall the aliens at the communications array. As the mothership rallies against the Missouri, Alex uses their last shell to destroy the communications array. All hope is lost for the Missouri and those onboard until the fighter jets arrive in time and destroy the mothership, saving the Missouri and eliminating the alien threat.

A ceremony is held to honor the military personnel, where Alex is promoted to lieutenant commander and presented with both a Silver Star and his brother's posthumous Navy Cross. After the ceremony, Alex asks Sam's father Admiral Shane for her hand in marriage. The admiral initially refuses, but then invites Alex to lunch to discuss the matter. In a post-credits scene, three teenagers and a handyman in Scotland discover a crashed alien pod. When they open it, an alien hand reaches out, and they run off in terror.