In the year 2044, time travel has not yet been invented but in 30 years it will have been. When the mob wants to get rid of someone, they will send their target into the past where a looper, a hired gun, like Joe is waiting to mop up. Joe is getting rich and life is good until the day the mob decides to close the loop, sending back Joe's future self for assassination.

Using massive piloted robots to combat the alien threat, earth's survivors take the fight to the invading alien force lurking in the depths of the Pacific Ocean. Nearly defenseless in the face of the relentless enemy, the forces of mankind have no choice but to turn to two unlikely heroes who now stand as earth's final hope against the mounting apocalypse.

The attempted assassination of the American president is told and re-told from several different perspectives.