A group of terror-stricken high school classmates awakens to a chilling scenario -- they're confined in a chamber of horrors, desperate for answers.
As the girls desperately try to find ways to escape, they gradually key into a commonality that brings them all together in the room.
When the girls fear their captivity is retribution for an incident with a classmate, they point fingers as to who was at fault to save themselves.
The captives begin to string together clues and offer up confessions to solve the riddle as the table is cleared and set for new horrors.
A new concoction of riddles are offered into the mix as the remaining students decipher several seemingly unrelated incidents at school.
The girls finally realize that their antics at school have had profound, negative consequences -- and their victims may be seeking revenge.
In a heartbreaking twist, one student confesses to the actions that may have led to the very reason the seven girls remain captive in the room.
A horrifying truth is uncovered as the captives trace back the chain of events from last year that led to the alleged suicide of one of their friends.
While recalling memories of their friend Miho's father, the hostages uncover a secret relationship between two of the remaining girls in the process.
Suspicions lead to the possibility that the mastermind has been sitting amongst them all along, posed as a fellow captive and keeping watch.
With the list of culprits exhausted, the final captive comes faces to face with the individual who's been scheming revenge.
The encounter between the last captive and the captor escalates dangerously when they see a glimmer of hope that may change their fate.
The story rewinds to the blissful, bygone days of friendship, giving further context to the terror the students will eventually face.