What did we see that day? Was it real or an illusion? In 2036, world-class photographer Ryosuke Fujii returned to Lake Biwa. He went to the museum to see the dinosaur model on display there. This was an animal derived from the prototype of the Biwasaurus in the past. 20 years ago, the 11-year-old Ryosuke ran around to find the truth. He believed that the Biwasaurus was real. But Ryosuke had sealed everything in his heart.