High school student Shun Takahata leads an uneventful and mundane life, often finding himself bored with his daily routine. However, everything takes a dramatic turn when he is unexpectedly thrust into a deadly game known as daruma san ga koronda. A sinister twist emerges when the Daruma doll, which turns towards the blackboard, exposes a button on its back that students can press in hopes of ending the dangerous game. However, the stakes are high: should the doll spin back to look upon anyone in motion, their heads will explode. In a tragic and horrifying outcome, Shun is the only student left alive after this first round.
After the chaos of the game fades, Shun desperately seeks out his childhood friend Ichika, and together they navigate to the school gym. Here, they participate in another perilous game called Maneki Neko, which involves throwing a basketball-sized bell into a hoop around a colossal cat doll’s neck. Failure to make the shot results in death. Together, Shun and Ichika cleverly devise a plan to deceive the cat and succeed with the assistance of Takeru Amaya. Yet, in a shocking turn of events, Amaya murders the remaining students who did not aid them, declaring that the unworthy do not deserve to survive. After a brief altercation between Shun and Amaya, both are knocked unconscious by a cloud of sleeping gas emitted by the giant cat.
As the narrative unfolds, it becomes apparent that high schools around the globe are being subjected to identical terrifying trials. Shun awakens in a massive cube hovering ominously over Tokyo, alone with several other students, including a new acquaintance, Takase, who quickly develops a connection with him.
The next challenge they face is Kagome Kagome, where students are blindfolded and must deduce which of four floating Kokeshi dolls stands behind them. Several classmates tragically fail and meet their demise before Shun cleverly manipulates the Kokeshi doll into revealing its position, thus securing a victory for himself. Among the prizes, one Kokeshi transforms into a key that unlocks a door, allowing Shun to reunite with Ichika and Amaya.
Following this, the group faces a perilous situation with the game of Shirou Kuma, where a gigantic polar bear poses a series of questions that students must answer truthfully. A single lie results in grave consequences, as the group has to identify whom they believe is the liar, leading to the death of Takase and another student. In a startling moment, Shun deduces that the bear itself is the deceiver, not any of the students present.
The tension reaches its peak in the final game, held under the name matryoshoka. Remaining players draw lots to identify a "demon." Those not chosen must hide, and if the demon’s face is seen, they will be captured. The aim is for the demon to retrieve a can and set it within a designated circle; should this can be toppled before the demon can capture three players, it will explode, sparing everyone except the one who kicked it. Amaya is selected as the demon, leading to a tense standoff where all but Shun are captured. In a desperate maneuver, Shun dons a suit of armor and helmet to conceal his identity from Amaya. However, Amaya seizes the moment and captures him. Yet, in close quarters, Shun manages to restrain Amaya just long enough to kick the can, which, surprisingly, does not explode. Instead, the matroyshka dolls declare triumph, offering ice cream to the students with a promise of survival.
However, this semblance of joy is short-lived. The ice cream turns out to be a death sentence, with “you die” hidden on sticks inside for Ichika and the two other students before they are ruthlessly killed. In a haunting finale, Shun and Amaya stand atop the giant cube, watching as the citizens of Tokyo chant "God's children.” Defiantly, Shun proclaims that there is no god. Yet, the matroyshka doll asserts otherwise, enumerating the masters of the games as gods, before revealing an ominous figure, thus raising the stakes for Shun as he turns to confront this newfound reality.
