It gets you in the chest with the smallest possible crime: a kid breaks the leaf fossil his dad loved, says nothing, and then has to keep living in the same house as that silence. Rintarou's guilt is the whole engine here, and the film is patient enough to let it just sit there, unconfessed, while he goes back to the riverbank to dig like he can find a replacement in the dirt. Then Toshi shows up, strange and unexplained, and the movie never over-explains him either. This is Touko Yatabe's graduation work out of Musashino Art University, so it has that student-film honesty where nothing is loud and nothing is padded. The stratum metaphor lands because it's earned: layers pressing down, memory turning into stone. Slept on, and it deserves better than that.

Rintarou carries a secret that weighs on him: he has broken his father's cherished leaf fossil and can't bring himself to confess. The guilt stays with him through the summer. One day at the riverbank where he goes looking for fossils, he meets Toshi, a strange boy, and the two begin a stretch of summer adventures together. A short slice-of-life fantasy with a supernatural touch, the film was made by Touko Yatabe as her graduation work at Musashino Art University.