Zhao Yu, the top student in the second grade of the municipal middle school, has a petite figure that "will never grow taller", but hides a detective heart that is more persistent than anyone else; his partner Zhou Yu is calm and meticulous, and a notebook full of clues is his weapon for solving crimes. Due to a scream late at night in Building 3, the two were involved in the bizarre murder of Xu Yunxia, an old man living alone. The doors and windows were intact, he was killed with a knife, and the murder weapon was missing. All suspicions pointed to "the crime was committed by an acquaintance."
From the dusty registration book of the community's property to the black plastic bag behind the air conditioner unit; from the weird little shoes that don't fit to the forged voice alibi, the young detective team relies on the logical reasoning of the top students and follows the old grudge of "the husband died young and the son disappeared" to identify the real murderer step by step.
Community unit cases, campus suspicions, and police station co-investigations, they use the name of youth to break through the fog and protect justice with tacit understanding. When the season of falling cherry blossoms comes, an anonymous letter that says "Come to me" and half a page of ancient book fragments push them to an unsolved case that spanned time and space twenty years ago. From then on, the teenagers' path of investigation leads to a broader unknown.
Purpose: to use youthful sincerity to see the truth and justice; to use the light of reason to dispel the haze of human nature and the fog of the past.