Boston police officer Nick Walker is killed in the line of duty, only to find himself posthumously recruited by the Rest In Peace Department (R.I.P.D.), a heavenly law enforcement unit tasked with apprehending souls who refuse to move on to the afterlife. Nick is partnered with Roy Pulsipher, a former U.S. Marshal from the 19th century with a penchant for the old ways. Still grappling with his sudden demise and the need to leave his old life behind, including his beloved wife Julia, Nick reluctantly agrees to the terms of his service in return for the chance to find his killer and ensure Julia’s safety. The unlikely duo begin their mission to uphold cosmic balance and protect the living from increasingly malevolent and uncooperative spirits known as "Deados."

As Nick adjusts to the rules of his new existence, he learns to maneuver the humorous and often bewildering intricacies of the R.I.P.D. The pair uncovers a plot that threatens the stability between the living and the dead, as they track down these devious entities hiding among the living. Nick uses his instinct and policing skills, combined with Roy's experience and rough-and-tumble approach, to pursue leads and confront the Deados who are conspiring to bring chaos to the ordered world. With interspecies battles and the fate of the world hanging in the balance, Nick and Roy must rely on their newfound partnership to restore peace and enforce the eternal laws of the afterlife.