At the girls' high school where Akane Ayukawa works as a teacher, a live video of a suicide posted by someone on a video site has become a hot topic. Rumor has it that everyone who happened to watch the live broadcast also died. Meanwhile, her student Noriko Morisaki dies under mysterious circumstances. Detective Koiso and his friends are suspicious of multiple suspicious deaths, and as they investigate, they come to the common denominator that they all watched the video right before the deaths.