Grade: C

John Green need have no fear of “Then Came You,” which is rather like “The Fault in Our Stars” played in a somewhat lighter vein. Peter Hutchings’ teen dramedy has a couple of attractive young leads in Asa Butterfield and Maisie Williams, but ultimately doesn’t amount to much.

Butterfield plays Calvin Lewis, a young man with one of those sad pasts we hear about in flashbacks and revelations that are dribbled out over the course of the picture. A troubled lad who dropped out of college, where he never fit in (of course), he’s moved back home, where he lives with his supportive father Bob (David Koechner) and his mother Ellen (Ann Osmond), who suffered a nervous breakdown years earlier and has never recovered.

Calvin works as an airport luggage handler alongside his dad and older brother Frank (Tyler Hoechlin), whose wife is expecting. His off time he spends mostly worried about his health. He’s certain he has cancer of one sort or another, and pesters his GP so much that the doctor suggests he participate in a cancer support group so he can meet some people really afflicted with the disease.

It’s there that he meets Skye (Williams), the prototypical free spirit who at first comes across as intensely irritating but before long will be pegged as lovably goofy. She literally pursues Calvin, enlisting him as her confederate in completing her “bucket list” (cue a flurry of montages in which the duo engage in a variety of slapstick sketches). At one point in their shenanigans, Calvin catches the eye of buffoonish cops Al and Mya (Ken Jeong and Briana Venskus) and is in danger of being arrested; but Al’s dad is also in that support group, and he and his partner becoming helpmates to the pair, refraining from giving them tickets and assisting in their pranks (at one point giving them a lie detector test—Skye wants to beat it as part of her list of goals).

Skye will also help Calvin break through to the older woman he’s infatuated with, a flight attendant named Izzy (Nina Dobrev), who will eventually invite him onto her plane despite his aversion to flying (and the incredulousness of her colleague, played by Tituss Burgess). But there’s a problem that will become an obstacle: Izzy believes that Calvin has cancer, and he procrastinates about telling her the truth. Of course, she has a thing about guys who aren’t honest, so you can see where that’s headed.

One thing you can admire “Then You Came” for—it doesn’t cop out at the end. Skye really is terminal, and though her final days are treated rather manipulatively (Calvin’s final gift to her, intended to be endearing, is actually a mite creepy, and you can bet that her hospital stay will coincide with a happier event that makes it all very sentimental, like the message of “The Lion King”), at least it doesn’t simply opt for a miraculous recovery. Of course, the true recovery is Calvin’s, and the picture milks that for all its worth in the closing minutes.

While you can applaud a few of its choices, though, overall this is a picture whose heart might be in the right place but is sabotaged by way too many clichés and too much sappiness. The combination undermines committed work from Butterfield and Williams, who are both driven to play things too broadly, though both do better in the final act. The supporting cast is fine—apart from Burgess and Jeong, both of whom mug ferociously—and the technical side of things is adequate (with nice cinematography by Andre Lascaris).

With smarter writing and a bit of subtlety, “Then Came You” might have been a charmer; as it is, it wastes the efforts of a talented cast.