New Paramount pic Spontaneous, which stars Katherine Langford (Knives Out) and Charlie Plummer (Looking for Alaska), begins with a bang. A big, wet, sloppy, chunky, gooey, meaty bang. You see, a teenage girl explodes in the middle of what would otherwise be just another class in just another day in the fairly routine existence of your average high schooler. But to just spontaneously combust in front of your peers with no warning and no protocol on what to do in the aftermath? Well, that's anything but fairly routine.

Spontaneous is technically labeled along the lines of "science fiction," "fantasy," and "comedy," but there is more going on here than meets the eye — and that's refreshing as hell. For this, we can thank the movie's director, Brian Duffield (Underwater, Netflix's The Babysitter), who has also adapted the script from Aaron Starmer's 2016 novel of the same name. Duffield's script retains the heady mix of cheekiness and heart that also anchored his script for The Babysitter. As a result, Spontaneous is constantly shifting around in tone, but it navigates those shifts well and allows room for surprise in a way that makes Duffield's efforts feel exciting to watch.

Duffield has crafted a compelling, insightful story with the raw materials of Starmer's book. Spontaneous is seen through the eyes of high school senior Mara Carlyle (Langford). Mara is a slightly jaded straight-shooter who, in the wrong hands would be the walking embodiment of the sentiment, "I'm not like the other girls." This is thankfully not the case. The first spontaneous combustion has a profound impact on Mara and the rest of her senior class. It changes and challenges her in ways she doesn't expect. The impact only grows and intensifies as more teens continue to spontaneously combust around Mara, her new boyfriend Dylan (Plummer), and their friends.

As you might expect, living in a constant state of fear and wondering when the other shoe is going to drop and it might be your time to explode into a viscera puddle has some strange and serious effects on these teens. With zero answers about why this horrifying thing is seemingly targeting one grade's worth of kids in one high school and with no answers to be offered from the team of doctors and specialists who take them all into quarantine to examine them, things can get weird real quick. As Spontaneous descends deeper into the mystery of these spontaneously combusting teens, a variety of survival responses are triggered. Mara and Dylan embrace their relationship and form a united front quickly while also embracing life to its fullest; who knows when the ride will end? Other kids descend into mourning for the friends they've lost, becoming walking memorials and remaining stuck in the sad. And there are some who try to just plow forward and focus on living life, even if it's unspectacular because that's all they can do.

One of the biggest highlights of Spontaneous is the chemistry between Langford and the rest of the cast. Count on this cast to make even the movie's darkest moments feel light and accessible. With a fairly snappy, sharp, sensitive script in hand, Langford gets to work in some new shades we haven't yet seen her in. At various times charming, cynical, vulnerable, or sarcastic, Langford succeeds as the heart of Spontaneous. Her scenes with Plummer are a true delight, as the two just bounce off each other with relative ease. Their relationship is believable in part because they balance one another so well. It's also equally wonderful when Langford shared the screen with her movie parents, played by Piper Perabo and Rob Huebel.

Spontaneous' absurd and morbidly funny premise transforms into a movie concerned with human responses to sudden tragedy. When there are no answers, no theories, and no concrete reasons behind destruction — or when your life seems to be, quite literally, blowing up around you — how will you respond? This is where the tonal shifts I mentioned earlier come in. From Mara's perspective, Spontaneous takes on a slightly nihilistic tinge and for good reason. Mara is always close by when someone explodes and she is always left shocked and covered in the blood spray of someone she once knew. That can take a psychological toll and they way Spontaneous chooses to deal with Mara's attempts to regain some control of her life in the midst of pure chaos feels honest and engaging. Unfortunately, Spontaneous weakens when it leans into general, vague platitudes along the lines of "You've gotta live while you can because you never know when you're going to die," something it does more than once. But when it finds specificity and takes some time to sit with the real, heavy fallout of living in a world where brutal death is reality, it succeeds.

Spontaneous arrives a time when, much like the characters in this story, we're living through a chaotic and uncertain time. Being offered a chance to process all of the messy feelings that come up from living in this current reality through a story that doesn't resemble said reality feels like a relief. Spontaneous is a refreshing success (even when it stumbles) because it is full to the brim with heart, insight, and best of all, some genuine laughs that we all need right now.

Rating: B-

Spontaneous will receive a limited theatrical release on Wednesday, October 2, and will be followed by a VOD release on Sunday, October 6.

Allie Gemmill is the Weekend Contributing Editor for Collider. You can follow them on Twitter @_matineeidle.