Summer, 2000. Eleven-year-old Yusuke and his classmates are camping in a woods when suddenly they see a bright light streak over the treetops and into the woods. The boys take off into the woods towards the light. There in the ground, growing, they find a small round metallic object. Just as Yusuke reaches to touch it, the mysterious object up pops a set of eyes and the object says: "I am Tetra, I meet Yusuke". Yusuke replies "Your name is Tetra? Cool". Tetra creates wonderful gadgets using "never-seen-before" technology. It would appear Tetra was designed with artificial intelligence. But where did Tetra come from and what is its purpose? As the relationship grows between Yusuke and Tetra, these questions are answered.