Then and only then, when the snow is white

Five years ago, the body of a young student was discovered on a quiet school campus. The circumstances of her death remained a mystery: the room was locked from the inside, and there were no traces on the perfect surface... of the snow outside. The investigation was hastily closed, ruling it a suicide.

Years later, bored members of the student council led by Feng Luyue decided to investigate this crime out of curiosity. However, their harmless curiosity unexpectedly turned into a deadly reality when a new murder occurred on the campus. The victim was a girl known for bullying others, and the circumstances eerily mirrored the case from five years ago.
 
It becomes clear: the killer has been nearby all this time. To stop him, Feng Luyue must untangle the web of lies from the past before the snow conceals the truth forever.