At the beginning of the game, two people make their way to a mysterious island. Apparently, they are searching for a mysterious person of interest.
A young, silver-haired woman wakes up on a beach, only to be awakened by Yuki Maeda note . She asks him what is going on, and he states that he has no idea. She also states that she doesn't know anything; about her past or who she is. Yuki also states that he is from Hope's Peak Academy, which the woman also doesn't know. Yuki now decides to call the woman, "Sora". Both of them agree to investigate the island, hoping to find other people on it. During their investigation, they also discover a huge boat, named "Monocruise", which can hold many people.
After meeting with the rest of the students, Sora and Yuki meet up, departing that they still have no clues. Both of them gather the students. One of them, Yuri Kagarin note , suspects that they're kidnapped. However, Setsuka Chiebukuro note thinks they should go for a swim. Few of them agree, while some refuse. In the midst of the swimming activity, however, Sora blacked out, alongside the other students.
Sora wakes up, only to see that night dawned on them. After a while, an announcement plays, revealing a figure that requests their presence at Utsuroshima Park for the opening ceremony. Upon gathering, the figure reveals himself as Monocrow, the "teacher" in charge of the "field trip". Monocrow states the rules of the Killing Game; that one must kill another and get away with it should they seek to leave the island. However, during the speech, the enigmatic Mikado Sannoji note warns the students not to get any closer to Monocrow. He states that he is a member of Void, and is seeking to protect them at any cost. In the wake of that, a gunshot is fired that hits Mikado's mask, exposing the other half of his face. The people who fired the gunshot reveal themselves to be Rei Mekarunote and Teruya Otori note , former students of Hope's Peak Academy and members of the Kisaragi Foundation. Both of them have been hunting down Mikado for his supposed crimes; including the fact that he is the supposed Mastermind of the Killing Game. Mikado stands by for a while, before making his move. Using his magic, he incinerates Rei and sends Teruya flying off the island. Then, he comes forward to the students, confessing that he is, indeed, the mastermind who kidnapped them. Still, the Killing Game shall continue. As the students comprehend the situation, one of them, Syobai Hashimoto note attempts to stab Yuki with a knife, but Sora takes the hit, rendering her unconscious.
The Killing Game begins.
Sora wakes up in an infirmary, attended to by Yoruko Kabuya note . She states that Monocrow disavowed Syobai's action and that Syobai himself bandaged her. The students have reportedly gathered at the diner, with Yoruko urging her to participate. Sora agrees.
Sora meets up with Syobai, who reveals that he treated her because he was "sorry".
