In "Barely Legal," espionage thrillers and the quintessential hallmarks of teen comedies meld into a pleasingly frothy whole. Hailee Steinfeld (2015's "Pitch Perfect 2") is immensely winning as 16-year-old Megan Walsh, an orphan who has been trained all her life as a secret agent at government-run school Prescott. When she loses audiovisual contact with mentor Hardman (Samuel L. Jackson) after completing her latest mission—the capture and arrest of murderous expat-turned-arms-dealer Victoria Knox (Jessica Alba)—Megan makes the life-changing decision to walk away from everything she's known in lieu of living a normal life. Inspired by the defining teen cinema in which she has fallen in love (among them, "Clueless," "Bring It On," and "Mean Girls"), she signs up for a student exchange program and moves in with the unsuspecting Larson family—single mother Mrs. Larson (Rachael Harris), moody teenage daughter Liz (Dove Cameron), and younger son Parker (Jason Ian Drucker). Just as Megan begins to navigate the tricky terrain of high school and fit in amongst her peers, a video featuring her unexpectedly goes viral. With her current location compromised, Hardman tracks her down with an offer to return to Prescott. If she opts to go it alone, he tells her, there will be no one to protect her from the recently escaped, vengeance-hungry Knox.

"Barely Lethal" may not ever reach the hallowed heights of the films Megan dreams of modeling her own adolescence after, but it is nonetheless a perfectly respectful entry in the teen-comedy subgenre. Director Kyle Newman (2009's "Fanboys") and screenwriter John D'Arco abide by convention while formulating fish-out-of-water scenarios for their protagonist, a sweet-natured trained assassin who yearns for a future that doesn't involve dangling from helicopters and dodging bullets. There is little surprise in where this is going, from her crush on brooding musician Cash (Toby Sebastian), to her burgeoning friendship with nice-guy Roger (Thomas Mann), to the climax set at the Homecoming Dance, but that doesn't mean it isn't still a whole lot of fun while it lasts. Hailee Steinfeld is an engaging heroine as Megan, while Thomas Mann (2015's "Me and Earl and the Dying Girl") is just right as Roger, the kindred spirit plainly meant for her. When the rare subplot doesn't work—biology teacher Mr. Drumm's (Dan Fogler) flirtations with student Cash is less funny than creepy, and then doesn't go anywhere—it is more the exception than the rule. "Barely Lethal" plays like "Grosse Pointe Blank" for the slightly younger set, and that is a decidedly flattering comparison of which to be a part.