The story takes place a little in the future. Guided by one particular song, young elementary school student Suzuhara Sorata, from the Heisei Era, is warped through a time skip to an unfamiliar place that looks much like the towns from the Meiji or Taishou period from his textbooks. In this world, he meets three young ladies and nine young men and joins them on a journey aboard the mysterious Norn ship, a giant globe that floats in midair.
Mikoto’s been kidnapped, and Sakuya, Masaume, and the others launch a search. With war on the horizon, they are forced to learn the truth about their world’s dark history.
Everything changed when Koharu joined the crew of Norn. The sins of the past forge an uncertain future and put the fate of the crew, and the world itself, in the balance.
The entire crew is still reeling from the effects of last night's strange dream. Just as things couldn’t get more uncomfortable, the ship is attacked again… from the inside.
With the journey ending soon, the crew decides to have fun with a dare contest. However, wounded hearts and hidden intentions threaten the safety of everyone on the ship.
With Koharu still missing, Kakeru returns to the surface to find her and his father. Meanwhile, Akito and Nanami prepare to reveal their secret to a member of the ship.
Following Sakuya’s vision of the near future, the crew hurries to rescue Koharu and Mikoto. On the island, Kakeru runs into Natsuhiko and Ron.
The group is finally reunited aboard the ship. The Reset weighs heavily on their minds, and Koharu fears the inevitable global consequences of their decision.