For all of its science-fiction connotations, and fears of dating your own grandmother, the irresistible idea of time travel rests on a single imponderable question: If you could do it over again, would you?
That question is asked in a variety of ways in "Safety Not Guaranteed," a sharply written and earnestly emotional comedy that blends a fantastical premise with deeply human characters.
The story begins with a classified ad (based on a real ad that launched an Internet meme): "Wanted: Somebody to go back in time with me. This is not a joke. You'll get paid after we get back. Must bring your own weapons. I have only done this once before. Safety not guaranteed."
An obnoxious Seattle magazine writer, Jeff (Jake Johnson, from "New Girl"), tells his editor he wants to find the ad's writer. So he dragoons two interns, sarcastic Darius (Aubrey Plaza) and nerdy Arnau (Karan Soni), and drives to Ocean View, a small seaside town, to find the guy.
Darius tracks down the writer, a lonely guy named Kenneth (played by Mark Duplass). After Jeff fails to gain Kenneth's confidence, he sends Darius undercover to try to connect with the putative time traveler. Darius, talking tough, gets Kenneth's attention and soon she is training under Kenneth for their impending mission to go back to the year 2001, which has personal significance for both of them.
The matter of whether Kenneth really has a time machine, or is merely delusional, becomes more complex as he and Darius start falling for each other.
Jeff, meanwhile, reveals his ulterior motive for taking a trip to Ocean View: a chance to reunite with Liz (Jenica Bergere), with whom he shared a romance some 20 years earlier.
Screenwriter Derek Connolly, who won the Waldo Salt Screenwriting Award at this year's Sundance Film Festival for his work here, neatly juxtaposes Darius and Kenneth's time-travel preparations with Jeff's quest for his lost youth finding in both a desire to reach back for something missing in their lives.
What's most touching in director Colin Trevorrow's film is how Kenneth's skittish paranoia and Darius' wary cynicism each start to melt away as their relationship deepens.
The performances are key. Duplass, who's establishing himself not only as an indie director (making "Jeff, Who Lives at Home" and "Cyrus" with his brother Jay) but as a solid Everyman actor ("Darling Companion," "Humpday"), captures Kenneth's longing to find lost love and to be appreciated for his scientific brilliance.
But the revelation here is Plaza, shaking off the cynical pose that has become her comic trademark (as seen in "Scott Pilgrim vs. the World" and most famously on the sitcom "Parks and Recreation") to find the warm, vulnerable human being underneath. It's a beautiful, star-making performance that ensures that "Safety Not Guaranteed" will win your heart.
'Safety Not Guaranteed'
Time travel is the vehicle for this sweet, smart romantic comedy about the search for second chances.
Where • Broadway Centre Cinemas.
When • Opens Friday, June 22.
Rating • R for language, including sexual references.
Running time • 85 minutes.