The film is a “metafiction” inspired by a true incident in which a 16-year-old girl who poisoned her mother with thallium, earning the nickname “Thallium Girl”. Actress Yuka Kuramochi plays the girl as she relays her day-to-day thoughts to a documentary filmmaker.
The girl is intensely interested in science, dissecting various insects and animals while also viewing herself as a potential subject. Soon, her experimentation extends to her unstable mother, who is obsessed with maintaining a youthful appearance. The girl begins secretly administering small doses of thallium to her and recording the results.
However, over time her interests turn inward and she decides to begin a new experiment…