Seikaisuru Kado

A colossal, perfectly geometric cube suddenly appears in the sky above Haneda Airport, disrupting international flights and sending the world into a frenzy. This mysterious entity, dubbed "Kado," defies all known laws of physics and logic, leaving humanity baffled. When Japan's top negotiator, Koujirou Shindou, steps forward to make first contact, he finds himself drawn into an unprecedented dialogue with an otherworldly being, Yaha-kui zaShunina, who claims to merely want to "interact" with Earth. What begins as an astounding exchange of cultures and knowledge quickly escalates into a global phenomenon, as the true intentions behind Kado's arrival begin to unfold. As governments and scientists scramble to understand this impossible visitor, Shindou finds himself at the center of a cosmic chess match, where the fate of humanity hangs in the balance. Prepare for a mind-bending exploration of first contact, diplomacy, and the very definition of progress.

✦ AI-drafted summary