Once a prize-winning violin prodigy, Hajime gave up on music after his father, professional violinist Ryuuji Aono, was involved in a scandal that led the media to harass his family. Now living alone with his mother and entering his final year of middle school, Hajime struggles to find a new career path. However, the sound of his classmate Ritsuko Akine playing the violin inspires Hajime to dream of a musical career once more. With the help of Ritsuko, Hajime prepares to take the entrance exam for the prestigious Umimaku High School. But if he wishes to join Umimaku's orchestra, Hajime must overcome his past trauma and open himself up to new musical horizons.

"Orn Doula, today will be your last day in the party." Orn, once a skilled Swordsman, had adapted to the role of Enchanter to fill a crucial gap in the Hero Party. However, one day, the party leader abruptly dismisses him, claiming his skills are lacking. Brander a "weakling" and a "jack of all trades, master of none," by his former comrades, Orn is cast out without a second thought. Determined to start anew, he returns to adventuring—this time as a Swordsman, the role he originally excelled in. But his time as an Enchanter was far from wasted. The experience, knowledge, and countless original spells he developed in the Hero Party have forged him into a warrior unlike any other. Now, armed with an unconventional set of skills, Orn is ready to carve his own path—one that will prove his true strength to the world.

The story moves on to a new stage──half a year has passed since the release of "POP IN 2." Thanks to Mem-cho's hard work, B-Komachi are on the verge of their big break. Aqua continues to grow as a personality, while Akane advances on her path to becoming a skilled actress. Meanwhile, Kana has lost her usual cheerfulness. Finally, in her quest to uncover the truth behind Ai and Gorou's deaths, Ruby rises through the entertainment industry—using lies as her weapon.

Yuki wakes up to find herself in an unfamiliar manor, wearing a maid uniform and lying on a luxurious bed. Soon, she discovers five more girls, all dressed the same as her. This is the Ghost House, and the only way they can survive is to make it through the traps that lie in wait—deadly games full of blowguns, buzz saws, locked rooms, and weapons. It's a hopeless, terrifying situation for everyone there...well, everyone except Yuki. After all, this is her career at seventeen. Do you think that's odd? She would agree. But that's how some people are—they earn their living playing death games.