Stella Meghie’s adaptation of Nicola Yoon’s 2015 novel, “Everything, Everything,” let’s most things fall to ruin, but does one thing quite well. Amandla Stenberg plays Maddy Whittier, a girl with severe combined immunodeficiency (SCID). She’s trapped in her house because of her illness but takes interest in her new neighbor Olly Bright (Nick Robinson).

The film follows their intimate relationship as they navigate Maddy’s shoddy immune system and Olly’s abusive home life. Stenberg and Robinson have the chemistry to blend a considerable amount of wonder and curiosity into their characters. They truly seem like two people utterly absorbed in a shared happiness greater than the sum of their misery.

Thank goodness they’re the heart of the movie. Their performances make it worth watching. It’s clear that both Meghie and writer J. Mills Goodloe cared the most about them. Because Maddy and Olly’s scenes are the most artistically intriguing.

Many have a Wes Anderson-esque feel to the camera work and dialogue. The film even has some interesting ideas for getting around the limitations of their dialogue scenes.

You see, one of Maddy’s interests is architecture. She crafts models of everything from a mid-century diner to a vast library. In each model, she puts a toy astronaut, longing to live as adventurously as he does, but knowing it can only be in her imagination.

So, while Maddy and Olly’s early conversations are over text messages, the movie doesn’t force us to watch large walls of dry shorthand. Instead, Maddy pictures them talking in her diner or library, while the astronaut fails to drink a milkshake or files books in the background.

These scenes are breaths of openness in a movie where we are mostly confined to Maddy’s house. This tight focus isn’t bad. We see the periphery of Olly’s fights with his father, as well as everyone except Maddy getting to come and go from her home. It conveys her sense of claustrophobia well, but it also means that the few other characters are put under increased scrutiny. And this is where “Everything, Everything” falls apart.

Maddy’s mom (Anika Noni Rose) is perhaps the most broken piece, merely used as a tool to move the plot. We get a brief moment with her early on, to show that she cares and worries for Maddy, but she then disappears. She only returns when the movie needs her to push Maddy closer to running away.

Mom barely meets Olly and the next time she is on screen, it’s to confront Maddy about their relationship. She says she feels conflicted about them being together. And while it’s easy to assume that long ago she decided Maddy’s health is more important than her happiness, the movie never revisits that because of Maddy’s new relationship. This is crucial not only to mom as a character, but to the flow of the plot. But because the film foregoes this part of her development, the rest of its running time is spent explaining Mom’s choices, rather than allowing us to feel the emotional implications of these decisions.

“Everything, Everything” tries halfheartedly to make up for this by having Maddy’s lifelong nurse, Carla, be gentle and nurturing, but in doing so opens up a similar problem.

Carla is the first one to let Olly into the house, so he and Maddy can meet in person. Maddy only has to beg once for this. Carla’s enabling is used to move the plot the same way Maddy’s mom’s harshness is. These haphazard characters just aren’t given the time to become as well rounded as the movie needs them to be. The B-plot plays a significant enough role that their sloppiness makes the movie lose the impact it needs in its final moments.

Without spoiling the ending, the lack of attention paid to everyone around Maddy and Olly dissolves most of the triumph in their love. They are charming, but there’s too much introduced for them to be able to carry the whole movie.

So, while “Everything, Everything” wants to pit the simplicity of young love against the complexity of family, it shouldn’t. It should just be one thing: a love story. And if it did that, it might have had a shot at capturing everything it wants to say.