Many people had no idea who Aubrey Plaza was before she began quietly stealing scenes on NBC’s “Parks and Recreation,” but once she began popping up in comedy films here and there, her distinctive brand of deadpan surliness began to get her some attention. With “Safety Not Guaranteed,” Plaza gets a huge chance to shine, and her performance alone makes the film worthwhile.

Plaza plays Darius, an intern at a Seattle magazine. Another intern, Jeff (Jake Johnson), finds a compelling ad in the classifieds asking for a partner in time travel and ominously declaring “safety not guaranteed.” He asks Darius and fellow intern Arnau (Karan Soni) to go track down the story with him. Darius quickly learns that the ad’s writer is Kenneth (Mark Duplass), a possibly insane but undeniably sweet grocery store worker who may or may not be legitimate in his quest.

“Safety Not Guaranteed” operates in several genres at once and juggles the ensuing demands of its narrative marvelously. The film has the setup of a mystery, a bit of romance (notably in a thematically appropriate offshoot about Jeff chasing down a fling from his past) and even a dash of conspiracy thriller and science-fiction. But above all, it’s a comedy, and the film is wise to never lose sight of that. It’s funny throughout, but its jokes are drawn much less from the plot than from the script’s fantastically developed characters and what we learn about them over the course of the movie.

Plaza’s Darius isn’t who one would normally build this type of story around, usually focusing on the investigative reporter or the paranoid aspiring time traveler, but she makes for an interesting central character. The role is perfectly suited to Plaza, using her curmudgeonly demeanor to mask a sweeter, wounded side, and when the film goes for truly poignant moments, it’s because of her honest performance that they work.

As for the supporting cast, director Trevorrow pieced together a strong group of players, each of them bringing something distinct but essential to the table. Duplass plays his Kenneth as a fundamentally good guy with a strong passion and seriousness for his mission, and the dynamic that his character develops with Darius is unexpectedly tender.

Soni’s awkward intern character looking for resume experience without any real memories to go along with it gives the film tons of unexpected huge laughs, and his effeminate delivery and harmless creepiness is brilliantly deployed throughout. There are several scenes in the film where Soni, Plaza and Johnson are kicking around ideas, and the chemistry between the three of them is so strong, the jokes they bounce off of each other so sharp that they’re some of the film’s highlights.

“Safety Not Guaranteed” may focus on Plaza’s character, but it’s by no means a one-woman show. Great performances showcase a heartfelt, funny script from Derek Connolly, one that’s never satisfied to rein itself into any single genre but still makes some beautiful insights to humanity and our desire to know about our world and the people in it. The film ultimately builds to a triumphant, cathartic conclusion, a daring, unexpected way to end a film that bills itself as a typical comedy. “Safety Not Guaranteed” doesn’t fit into any particular box, and it’s proud of it, which is something that makes the film worth seeking out.