Plot

A soldier fighting aliens gets to relive the same day over and over again, the day restarting every time he dies.

An alien race has hit the Earth in an unrelenting assault, unbeatable by any military unit in the world. Major William Cage (Cruise) is an officer who has never seen a day of combat when he is unceremoniously dropped into what amounts to a suicide mission. Killed within minutes, Cage now finds himself inexplicably thrown into a time loop-forcing him to live out the same brutal combat over and over, fighting and dying again...and again. But with each battle, Cage becomes able to engage the adversaries with increasing skill, alongside Special Forces warrior Rita Vrataski (Blunt). And, as Cage and Vrataski take the fight to the aliens, each repeated encounter gets them one step closer to defeating the enemy!—Warner Bros. Pictures

When an alien race called Mimics invades and destroys Europe, London is the last resistance in the Old Continent. General Brigham plans an attack to France expecting to defeat the Mimics and orders Major William Cage, who is an American public relation officer, to cover the invasion. However Cage does not accept the assignment and threatens General Brigham to expose the casualties. He is arrested, accused of desertion, demoted to private and assigned to fight in the invasion under the command of the tough Sergeant Farell in the Heathrow Base. Humans are slaughtered in the invasion and Cage kills a Mimic and is sprayed by his blood; in less than five minutes combat, Cage dies. Surprisingly he awakes in the Heathrow Base and relives the same day over and over after dieing. Each time, Cage tries to fix the deaths of his squad and he meets Sergeant Rita Vrataski who asks him to find her when he awakes in the base. Rita brings Cage to meet Dr. Carter who explains to him that he killed an Alpha and his blood has given the ability to reset time. Further, the last hope of earth is the destruction of the Mimic leader, referred to as the Omega, who is hidden. Will Cage and Rita succeed in their solitary mission?—Claudio Carvalho, Rio de Janeiro, Brazil

Before the numbing technological superiority of the omnipotent extraterrestrial menace known only as the "Mimics", mankind stands helpless, doomed to accept an ignoble fate. Having harnessed an unfathomable ability, the hordes of the ferocious alien race are practically invincible; unless we, humans, come up with an unexpected and drastic counter-attack. When the unseasoned officer, Major William Cage, learns firsthand the magnitude of the problem with his own life, he quickly realises that death is only the beginning--each blood-drenched battle with the formidable foes brings him back to square one, only with a dash of improvement in his fighting capacity. Perhaps now, Cage, his legendary brother-in-arms, Rita Vrataski, and the rest of the world have a fighting chance against the otherworldly opponent. Can we solve the enemy's enigma?—Nick Riganas

A race of aliens called Mimics has taken over continental Europe. General Brigham (Brendan Gleeson), head of humanity's United Defense Force, orders Major William Cage (Tom Cruise), a public affairs officer and former advertising executive, to cover combat on the beaches of France during the next day's assault on the Mimics. Cage objects to the dangerous assignment and threatens to use his public relation skills to turn the public against Brigham when the casualties start increasing from the invasion, for which he is arrested and knocked out. He wakes in handcuffs at a forward operating base at Heathrow Airport and discovers he has been labeled a deserter and put on combat duty, as a private, for the invasion of France under the command of Master Sergeant Farell (Bill Paxton).

The invasion is a disaster for the humans. Cage manages to kill a large Mimic, but dies as he is sprayed with its acid-like blood. He then wakes up at Heathrow the previous morning. No one believes his story that he knows the invasion will fail. He repeats the loop of dying on the beach and waking at Heathrow until he encounters Sergeant Rita Vrataski (Emily Blunt), who recognizes his ability to anticipate events and tells him to locate her the next time he "wakes up".

Cage finds Vrataski at Heathrow. Together they meet with Dr. Carter (Noah Taylor), a former government scientist and expert in Mimic biology. Cage learns that the kind of Mimic he killed in his first loop, an "Alpha", resets time when it is killed to give the Mimics an advantage in battle. Cage inherited this ability when he was doused in the Alpha's blood as they both died. Vrataski had this ability in a previous battle in Verdun but lost it after receiving a blood transfusion. Vrataski tells Cage that the Omega wanted humans to believe that they could win, so it allowed Vratasky to win in Verdun, so that humans put everything into their battle at France & get beaten. She tells Cage that they must hunt the Mimics' hive mind, the Omega & until that day Cage has to die each day to reset time. Carter tells Cage that the Omega has lost power to reset time to Cage & will be mentally looking for him. When Omega finds Cage, Cage will start having visions of the Omega's location.

Over succeeding loops Vrataski trains Cage into a more effective soldier. After getting discouraged from these loops he travels to London, there he realizes and sees the Mimics were planning on overrunning London during the invasion on the beach. He and Vrataski spend several loops learning how to survive the battle on the beach and get inland based on his vision of the Omega hiding in a Bavarian Alps dam. After numerous loops end in Vrataski's death, Cage decides to hunt the Omega alone, abandoning her and the rest of the invasion to doom on the beach. When he arrives at the dam, he discovers that the Omega is not there. He manages to kill himself before an Alpha can steal his blood and prevent him from resetting the day. Back at Heathrow, he tells Vrataski and Carter that his vision was a trick.

Cage and Vrataski adopt a new approach: they infiltrate the Ministry of Defence in search of a prototype built by Carter that will allow Cage to discover the Omega's true location. The device is a transponder which once attached to an Alpha, finds the location of the Omega. After several failed loops they obtain the device from General Brigham, which reveals that the Omega is located under the Louvre Pyramid in Paris (Cage stuck the device in his leg to activate the prototype as he is an Alpha now). They are injured as they flee & both are knocked unconscious so Rita is unable to kill Cage this time when he get injured. Cage's life is saved by a blood transfusion, but it removes his ability to reset the day.

Vrataski frees Cage and they return to Heathrow, where they convince his squad to help destroy the Omega. The team is given instructions not to kill the Alpha, as if an Alpha is killed, the Omega will reset the day & will know in advance of the squad's attack on Louvre. The other squad members sacrifice themselves to get Cage and Vrataski beneath the Louvre. Vrataski distracts a waiting Alpha while Cage advances on the Omega. The Alpha kills them both, but not before Cage primes and drops a grenade belt into the Omega's core, destroying it and neutralizing the other Mimics.

Cage's body absorbs the Omega's blood. He wakes up en route to his meeting with Brigham the day before. Brigham announces that Mimic activity has ceased following a power surge in Paris. Cage is never arrested and he goes to Heathrow, where he finds his squad mates, including Farell. None of them recognize him and treat him respectfully as an officer, as he is once again a Major. He meets Vrataski, who does not recognize him either. She asks what he wants, as she had many times before, and he smirks and laughs.