American Reunion does not get off to a good start. The first American Pie movie (not counting direct-to-DVD spin-offs) since 2003’s American Wedding begins with ever-hapless main character Jim (Jason Biggs) once again finding himself caught in a compromising sexual position by a family member, although now it’s his 2-year-old son rather than his eternally square dad (Eugene Levy). That opening scene sends the message that this is going to be a stale retread of decade-old gags, but thankfully the movie improves steadily from there. Somehow American Reunion manages to become a sweet, funny and even sort of touching rumination on getting older—along with the requisite gross-out gags.

It’s been 13 years since Jim and his buddies Kevin (Thomas Ian Nicholas), Oz (Chris Klein) and Finch (Eddie Kaye Thomas) graduated from high school, and now they’re headed back to their Michigan hometown for a belated reunion. It’s the perfect excuse to bring together nearly every major and minor character from the original movie, plus a few new faces. That makes Reunion seem crowded at times, and some of the significant characters from the past (including Natasha Lyonne’s Jessica, Shannon Elizabeth’s Nadia and Chris Owen’s Sherman) make only token cameo appearances. But writer-directors Jon Hurwitz and Hayden Schlossberg, the guys behind the Harold & Kumar series, come up with surprisingly compelling stories for all four main male characters, plus their hard-partying frenemy Stifler (Seann William Scott).

Kevin and Oz attempt to reconnect with their old flames (Tara Reid, Mena Suvari), Finch seduces a sexy bartender (Dania Ramirez), and Jim struggles to put the spice back into his marriage to Michelle (Alyson Hannigan). There’s plenty of vulgar humor along the way, and some of it, like the opening scene, does feel stale. As the characters start to take stock of their lives in the movie’s second half, though, Hurwitz and Schlossberg get at some bittersweet truths about growing up, without losing the series’ nostalgic heart. They even come up with a few poignant moments for Stifler. At the end of the movie, the characters vow to get together every year instead of waiting another decade, and it’s an unexpectedly welcome prospect.