Prologue.

Four students. Four dark secrets. And the killer who knows everything...

When a transfer student is found murdered in Classroom 12B, suspicion spreads like wildfire.
And it spreads fast.

The only thing these four classmates have in common? Lies-and the masks they wear to hide them.
But when detectives uncover damning evidence pointing to one of them-or maybe all of them-the question becomes:

How many masks must fall... before the truth finally bleeds through?