Mrs. Oyama lives near Grape Valley on Saturn's moon, Titan. Tetsuro Hoshino meets her when she takes him in after his decidedly cold welcome to her planet. She tells him where he is likely to find the kidnapped Maeter, and gives him her son's old Cosmo Gun for protection, along with a similar hat and cloak. After he successfully rescues Maeter, she allows him to keep the gun, and tells Tetsuro that if he ever encounters her son during his travels to pass along the message that she would very much like to see him again. Tetsuro does eventually meet him on Heavy Meldar, but Tochiro doesn't live long enough to make any further journeys.