Hiromu Shinbo (新保弘 Shinbo Hiromu), also spelled "Shimbo", is also studying at Seki cram school. He becomes involved with Ms. Shimizu after finding her in a park late at night because she had been unwittingly locked out of her house by her husband, who was too busy with his persocom. Shinbo is the original owner of Plum a.k.a. Sumomo, a miniature mobile persocom. Shinbo known also as Shimbo) is a student who attends classes at a cram school to do better on his entrance exams during the day. In the world where persocoms (pasocon, a Japanese contradiction of personal computer) exists, he has a mobile one, that he names Sumomo. It follows him around, are are close, but neither has romantic interest in the other. Sumomo provides him with information, and also has internet and a calling system (somewhat like a mobile phone) built in her. The best friend to this 19-year-old is Hideki Motosuwa. They both have much in common - they are of the same age, studies at the same school and lives in the same apartment complex - although their level of maturity are different. As a beginner in persocoms, Hideki always consults Shinbo on matters and operations regarding a persocom he found and is currently taking care of, Chii. Shinbo is a helpful and patient person, and sticks with his best friend through all the silly little things he does.