Pocket sized Ultra-Spec. ROBOT who's A.I. is far too advanced for the 21st century. Tetra appears to be a symbol for what the future holds. Tetra is capable of time-travel using a keyword; "juvenile". Is Tetra arekey to the future?
				Currently an electronics shop owner. Soichiro also lectures in college at Physics and he was a highly sought after computer game creation during his high school days he acquired numerous patterns for computer games. Kept secret from everyome is Soichiro's genious in Physics. Im his free time, he conducts research on time-travel. He befiriends Yusuke who is introduced to Tetra. This leads to major advances in his research on time-travel. Befriended by Yusuke and his classmates, Soichiro is the only adults they trust with the secret of Tetra. Soichiro has not lost his dreams or sense of adventure. He not only helps the boys but keeps a watch for eye on them.
						A sister in law of Misaki. She is a college student visiting Misaki during summer vacation. Her major is Physics and took Soichiro's class when he was an associate professor at her college. Her secret interest lies in "Spatiotemporal Transfer Employing Gravitational Physics" (Spatiotemporal Transfer=Space-Time Travel). Her strong opinion on Physics separates her from the other students. Gradually Noriko becomes compatriot of Soichiro in his Physic research.
						Happy, outgoing, faithful and sometime bold girl who is the favorite of Yusuke and his friends. She wishes to carry out her idea of connectiong Tetra to the Internet. She has confused emotions toward Yusuke.
						A little shy boy but he is full of curiosity. His room is filled up with all the junk and models scattered on the floor. Yusuke hides Tetra in a closet of his room. The gadgets Tetra creates are built from the junk Yusuke has scattered throughout his room. Yusuke is not confused about his emotions toward Misakiゥギ
						Careless but charming boy who is Toshiya's gopher. Hidetaka is the information source for everything happening at school and everything happening with his schoolmates. One day, his access to information will help his friends.
						Cheerful and outgoing, but a little precocious, he is the playmate of Misaki. He has never considered his feeling toward Misaki, but unconsciously he meddles in the relationship between Yusuke and