In a world where the government decides who lives and who dies based on intelligence tests, a group of students uncovers a dark secret and joins forces to bring down the corrupt system.

In a future society where overpopulation is a major concern, the government enforces a rigorous aptitude test called 'The Thinning'. Students who fail the test are eliminated to reduce the population. However, when a high school student discovers a hidden truth about the test, he teams up with his friend to expose a sinister conspiracy that could change the fate of their society.