Yuuichi Katagiri has battled financial hardships his whole life but has learned to stay content and positive thanks to his close circle of friends. To keep a promise he made to them, Yuuichi saves up enough money to join them on the school trip. But when the gathered money mysteriously goes missing, suspicion falls on two of Yuuichi's friends: Shiho Sawaragi and Makoto Shibe, who were in charge of collecting the payments. Although innocent, Shiho and Makoto take responsibility for the failure to protect the money when no one else comes forward. A few days later, Yuuichi and his friends receive mysterious letters which trick each of them into meeting up. Upon arrival, they are ambushed and knocked unconscious. They wake up in a mysterious room in the presence of "Manabu-kun," a character from a controversial children's show that stopped airing due to its malicious content. He informs the group that one of them indirectly gathered them together in order to settle a large debt. They are to play a "friendship game": a series of games that will test the strength of their bond and trust in each other. As the group's faith wavers due to the growing number of secrets and betrayals, Yuuichi must figure out who of his "friends" he can actually trust and ultimately discover the identity of the traitor.

Smart, refined, and strikingly gorgeous, half-Russian half-Japanese Alisa Mikhailovna Kujou is considered the idol of her school. With her long silver hair, mesmerizing blue eyes, and exceptionally fair skin, she has captured the hearts of countless male students while being highly admired by all others. Even so, due to her seemingly unapproachable persona, everyone remains wary around the near-flawless girl. One of the few exceptions is Alisa's benchmate Masachika Kuze, a relatively average boy who spends his days watching anime and playing gacha games. Despite his nonchalant demeanor, Masachika is the sole student to receive Alisa's attention. Unable to be fully honest, Alisa is frequently harsh on Masachika and only expresses her affection in Russian. Unbeknownst to her, however, Masachika actually understands the language yet simply pretends otherwise for his own amusement. As the odd pair continues to exchange witty and playful remarks, their relationship gradually grows more romantic and delightful—and Alisa might finally learn to freely convey her true feelings.

Mahiru Shiina is worthy of her nickname "Angel": she is a divine beauty loved by all, and she excels in both academics and athletics. Shiina lives in an entirely different world from Amane Fujimiya, her next-door neighbor. Despite living so close together, they have never spoken once. But their silence is broken when Fujimiya spots Shiina gloomily sitting on a swing amidst a heavy rainstorm and lends her his umbrella. When Fujimiya catches a cold the next day, Shiina wishes to return the favor for the umbrella by nursing him back to health. Believing that this would be their first and last interaction, he silently appreciates her kindness. However, Shiina—who can not help but worry about Fujimiya's lack of tidiness and proper nutrition—begins to cook and clean for him. As the unlikely pair spend time together in Fujimiya's apartment, they explore the true nature of their relationship and the gentle emotions that emerge from it.

With the ambitious Ryuusui Nanami on board, Senkuu Ishigami and his team are almost ready to sail the seas and reach the other side of the world—where the bizarre green light that petrified humanity originated. Thanks to the revival of a skillful chef, enough food is being prepared for the entire crew, and the incredible reinvention of the GPS promises to ensure safety on the open sea. Preparations for the upcoming journey progress swimmingly until Senkuu receives an eerie message from a mysterious source. More driven than ever, the scientist sets out to explore the new world and discover what it can offer for his scientific cause. Though the uncharted territories may hide unkind surprises, Senkuu, with a little help from science, is ready to take on any challenge.