The future of Earth is hidden on the surface of Mercury.

Aki Shiraishi is a high school student working in the astronomy club and one of the few witnesses to an amazing event--someone is building a tower on the planet Mercury. Soon, the enigmatic Builders have constructed a ring around the sun, and the ecology of Earth is threatened by its immense shadow. Aki is inspired to pursue a career in science, and the truth. She must determine the purpose of the ring and the plans of its creators, as the survival of both species--humanity and the alien Builders--hangs in the balance.

Aki Shiraishi is a high school student working in the astronomy club and one of the few witnesses to an amazing event--someone is building a tower on the planet Mercury. Soon, the enigmatic Builders have constructed a ring around the sun, and the ecology of Earth is threatened by its immense shadow. Aki is inspired to pursue a career in science, and the truth. She must determine the purpose of the ring and the plans of its creators, as the survival of both species--humanity and the alien Builders--hangs in the balance.