Battle: Los Angeles

Mysterious objects thought to be meteorites land in Earth's oceans near many major cities. These objects are revealed to be spacecraft containing hostile extraterrestrial life. Marines from Camp Pendleton arrive in Los Angeles, including SSgt. Michael Nantz (Aaron Eckhart), a 20-year veteran who lost his squad during his last deployment in Afghanistan. Nantz had planned to retire, but must replace the platoon sergeant from Echo Company, 2nd Battalion 5th Marines.

Under command of 2ndLt. William Martinez (Ramón Rodríguez), who graduated from The Basic School one month earlier, the platoon arrives at Santa Monica Airport, now a Forward Operating Base. The alien ground forces have no air support, and the Air Force plans to commence saturation bombing of the Santa Monica area. The platoon must rescue civilians from an LAPD police station in West Los Angeles before the bombing. As they advance through the city, they are ambushed and suffer casualties, but find a group of Army National Guard soldiers from the 40th Infantry Division, including Air Force intelligence TSgt. Elena Santos (Michelle Rodriguez). At the police station the platoon finds five civilians inside: A veterinarian named Michele (Bridget Moynahan), children Hector Rincon (Bryce Cass), Kirsten (Joey King), and Amy (Jadin Gould), and Hector's father Joe (Michael Peña). A helicopter arrives to evacuate the wounded Marines Simmons, Guerrero, Lenihan, and Grayston, but cannot take the civilians. An alien aircraft destroys the helicopter, killing everyone aboard.

The Marines commandeer a city bus for evacuation. They also find a wounded alien and, with the help of Michele, study the aliens' physiology, finding a weak point in the torso. They also learn that the alien aircraft are remote-controlled drones which track human radio transmissions. Santos reveals that her original mission was to locate the aliens' central command center, believing that its destruction would deactivate the alien drones. On the I-10 freeway, the bus comes under attack. Because the off-ramp is destroyed, the Marines rappel the civilians off the freeway. The Army personnel and Marines Stavrou and Mottola are killed, and Rincon and Lt. Martinez are wounded. Martinez sacrifices himself to destroy the enemy unit by detonating C-4 explosives inside the bus, leaving Nantz in command.

The survivors (Nantz, Santos, Cpl. Kevin Harris (Ne-Yo), Corpsman Jibril Adukwu (Adetokumboh M'Cormack), LCpl. Peter Kerns (Jim Parrack), Cpl. Lee Imlay (Will Rothhaar), Cpl. Jason Lockett (Cory Hardrict), and the five civilians) escape the bombing zone. A news report speculates that the aliens want Earth's water, which they use as fuel. The team waits for the bombing, but nothing happens. At the airport the Marines learn that the aliens destroyed the FOB and that the military is retreating from Los Angeles. Echo Company plans to escort the civilians to an alternate extraction point. Before they leave, Rincon dies from his wounds and Lockett, whose brother died under Nantz's command in Afghanistan, questions Nantz's ability to lead. Nantz and Lockett deal with their guilt and anger as Nantz lists the names, ranks, and service numbers of all the Marines who have died under his command from memory. They reach the extraction point and leave.

From the air, their evacuation helicopter has a power glitch and Nantz speculates that it is the location of the alien command center beaming radio energy to the drones. He decides to recon the area alone, but his team insists on accompanying him. Going underground, the Marines confirm the presence of a large alien vessel and return to the surface. Kerns radios in to request guided missiles, which Nantz will target via laser designator while the others defend the position. Kerns is killed when his radio broadcasts draw attention to him, and the command center, damaged but not disabled by the first missile, rises from the ground to escape. The Marines succeed in guiding another missile to the command center, which collapses. The alien ground forces retreat as their uncontrolled drones fall to the ground, and reinforcements arrive to extract the surviving Marines.

At a base in the Mojave Desert Nantz's team is greeted as heroes for their bravery. Other cities under attack will emulate their strategy. Despite orders to rest, Nantz's team rejoin the rest of the Marines in retaking Los Angeles.