Love is not convenient.

For all the words that poets have spilled trying to describe love over the years, it seems to me that it is easier to describe by explaining what love is not. Love is rarely on your schedule. It would be amazing if we could simply snap our fingers and have love whenever we want it, but if that were the case, it wouldn't be love. The pain that is a huge part of the experience is one of the reasons it matters. Love is not easy. Love is not casual. Love is not interested in what we want.

"The Fault In Our Stars" is a very simple story about two kids, each struggling with cancer, who find each other at the least convenient time and fall in love. I don't think any part of that sentence is a spoiler. It's just a description. The details are what matters, and the script by Scott Neustadter & Michael H. Weber, adapted from the well-loved novel by John Green, is very smart and fairly unsentimental, which works to the material's advantage. When you're talking about a movie that deals with two young people with cancer falling in love, the potential for that to be hugely sappy is overwhelming. I haven't read the book, but the film nimbly avoids most of the things I expected from it, and does so in a lovely, thoughtful way.

Hazel (Shailene Woodley) has been suffering with cancer for most of her teenage years, and while she seems to have made some peace with it, she's not some chirpy, unnaturally cheery inspirational example. She's just a normal kid who has the thing that has consumed every corner of the normal life she wishes desperately she could live. Her well-meaning mother (Laura Dern) is worried about Hazel being depressed, and she encourages her to join a local support group for other teens in the same situation. This gives director Josh Boone a perfect opportunity to work in a performance from Mike Birbiglia as the leader of the support group, and it also provides the perfect place for Hazel to meet Agustus (Ansel Elgort).

There's nothing about the narrative that's going to blow your mind in terms of surprising structure or shocking revelations. The movie calls it right up front. This is a love story. And, sure enough, it is. The reason the film works is because there is a lovely rapport between Elgort and Woodley in every scene. I thought he was going to bug me when he plays his first scene in the film. There's a really cocky arrogance to the kid, but Elgort is very good at showing us how that's a decision that Gus has made, an act he puts on to look brave, and both actors do an excellent job of showing us the small signs of the vulnerability that the kids feel knowing that they are grappling with the very real idea of dying.

Hazel resists the notion of falling in love with Gus because she considers herself a bad bet, a guaranteed disappointment. She feels like it's her job to keep everyone at arm's length so that no one will be too hurt when she's gone. The movie earns her eventual change of heart by showing just how Gus reaches out to her, and the small steps by which they gradually become indispensable to one another. I'll admit it… the film really got me when it gets into the actual connection between them and how it develops. And if the film has anything genuine to impart to its audience, it's not about the cancer or dealing with death… it's in the value the film places on love itself, and in showing what that really means.

I would love to spend a week sometime publishing all the hate mail I got whenever I wrote about the "Twilight" films, and specifically all of the mail that said that I must hate love and that I don't understand that feeling. That drove me insane, because I think the "Twilight" films are about many things, but love is not one of them. I don't recognize real love in any of the behavior we see in those movies. But here, I was really moved by how mature the connection is between Gus and Hazel. They look for strength in one another, but they also find themselves drawn to all the quirks and rough edges that define the other person. They are entertained by one another. They know how to be there when the other person is hurting. They ask for nothing from one another. I think the reason the film packs a punch when it hits that home stretch is because the film has made the case for just how important they've become to one another, how inseparable they are at that point, and it's really beautiful. The truth is that love never arrives on our perfect timetable, and it is an act of courage to reach out and embrace it when it is offered, and this film understands just how big and scary and amazing that can be.

The film ambles a bit, and I wish the subplot about a novelist who they reach out to looking for some answers, played by Willem Dafoe, had felt more like it was organic to the story instead of feeling like a left turn that doesn't quite pay off. It's a nicely-made film, but I wish it had taken some more chances visually to draw us into the private world that these two build with their love. None of that will matter to the fans who already love this book. They'll no doubt be destroyed by the movie, and I suspect most audiences will find themselves largely charmed by the young leads and the intelligent approach to a difficult subject.

"The Fault In Our Stars" opens in theaters on Friday, June 6.