Given its origin in a classified ad, placed as a joke, which sought a companion for time travel (“I have only done this once before”), Safety Not Guaranteed spins a surprisingly solid comedy about the inherently risky nature of romance.

Parks and Recreation’s Aubrey Plaza plays Darius, a magazine intern assigned to write a story about the ad; as she investigates, she finds herself slowly falling for its author, Kenneth (Mark Duplass), who insists that he really has built a working time machine and intends to go back to save another woman.

Weak subplots involving Darius’ obnoxious boss (Jake Johnson) and nerdy fellow intern (Karan Soni) are needed to pad out the running time, but Plaza and Duplass make a winning pair of misfits, and first-time screenwriter Derek Connolly has crafted a funny, touching sci-fi metaphor for the uncertainty involved in opening yourself up to another person.