Our main characters are Rōma (Natsuki Hanae) and Toto (Yuki Kaji), two Japanese high school students (this is Anime after all) from a small rural town. Toto has moved to Tokyo to continue high school with the aim of becoming a doctor. As the movie opens, he's returned to their town for a visit. They are joined by Drop (Ayumu Murase), a small guy wearing a dinosaur hoodie who's only slightly younger than they are. Drop is unofficially inducted into Rōma and Toto's "Don Glees" club, and together they attempt to set off fireworks (which almost all fail) and film the event with a new and expensive drone (which is blown away by the wind). Later that night there's a forest fire, which the local bullies on social media blame on the Don Glees. So the three of them set out to recover the drone, which they hope has footage to prove their innocence (there were a lot of fireworks going off that night - I don't think they specified what the event was). This takes them on a two day adventure of getting lost and camping with inadequate supplies, and there are revelations about each of the characters.
The teens behave in ways that are pretty accurate to their age group (15 and 16 years old), but I'd say that the movie is targeted somewhat younger than that - perhaps around 12. There's not a lot for adults in this teen coming-of-age tale among the juvenile pratfalls and heavy-handed life lessons - except the gorgeous artwork which continues throughout. Good for fans of the genre, won't convert new fans ... except possibly for that amazing artwork.