Alien monsters, dubbed "Mimics" by the people of Earth, ruthlessly occupy the planet — destroying major cities and claiming millions of human lives. The armies of all nations have united their forces to engage in a decisive battle against the countless hordes of aggressors.
Recruit Keiji Kiriya, unprepared and poorly equipped like many of his comrades, is thrown into the thick of battle, effectively condemned to death. Yet in dying, Keiji takes the life of an alien with him.
Then something incredible happens — Kiriya finds himself once again on the eve of that hellish day, and, caught in a time loop, he is now forced to fight and die, returning again and again to that same battle. But with each cycle, Cage grows more brutal, more skilled, fighting side by side with the legendary special forces soldier Rita Vrataski, who has destroyed more enemies than anyone else on Earth. And each repeated battle brings them closer to discovering how to defeat the alien invaders and break free from the temporal trap.
What awaits them and their mysterious ally — salvation or final death?