By Chris Honoré for Revels

While the premise of “What If" might seem, at first blush, a romantic comedy that is both trite and cliché-driven, it proves to be instead an engaging film that manages to find, surprisingly, its own sweet spot.

First the cliché: Two 20-somethings, Wallace (Daniel Radcliffe) and Chantry (Zoe Kazan), meet cute at a party, in front of a refrigerator, the enameled door covered in magnetized words, the purpose being to rearrange them into small maxims. They can’t resist. There is instant chemistry between the two as they verbally joust in a playful way.

Leaving the party, Wallace walks Chantry home to her flat and while treading water by the front gate she tells him that she has a boyfriend. They’ve already shared that she is an animator/artist and that he has recently dropped out of medical school. On a whim, she gives him her phone number, written on a page torn from her notebook, a page with a drawn selfie on the back, while suggesting, with a handshake, that they could be friends and maybe hang out sometime.

Later, sitting on the roof of his attic digs, Daniel, who is recovering from a recent breakup, let’s the page/selfie drift away in a breezy updraft.

Of course, their paths cross at a late-night movie (“The Princess Bride”), both there alone, and they go for coffee, picking up the stylized banter where they had left off at the party.

Wallace, finding himself attracted to Chantry, captured by her smart wit and adorable eyes, goes along with the just friends-arrangement, sitting stoically on his true feelings. Sophie insists to all that she is committed to Ben; nothing has changed other than she has a new friend.

And that’s the cliché. The outcome is a foregone conclusion. It’s just how the two manage to get there. And therein is the charm of this film. Kazan and Radcliffe are able to take this familiar template and give it new life through the sheer power of their performances and obvious on-screen chemistry.

Of course, the formula calls for obstacles to be overcome (one complication being Ben (Rafe Spall), Chantry’s boyfriend of five years), all the while Wallace is restraint and vow-challenged. Of course, the two attempt to prove that young, optimistic, hormonal and wonderfully enthusiastic men and women in search of “the one” can be friends without benefits. You know, buds to hang with, sharing creative riffs on life and its exigencies.

Naturally, it’s all this unwillingness to yield to emotions that are obvious while being teeth-grindingly denied that propels the movie forward from one vignette to the next.

Obviously, there is not a shred of originality in the story. But, not to worry; “What If” is endearing and consistently appealing. As are Chantry and Wallace.