In Tokyo's Shitamachi area, there is a second-hand bookstore called "Tokyo Bandwagon ~ Shitamachi's Extended Family Tales". It is well known around the neighbourhood, and has been the Hotta's family business for 4 generations. Kanichi, who is currently managing the bookstore, is the patriarch of the family. His son, Ganato, is a legendary rocker of his time. Ganato's second son, Ao, is the only one born of a different mother amongst his siblings. Ao is an ex-delinquent but is actually a very kind-hearted young man."The riddle of the disappearing encyclopedia", "The child left behind and the book that could open holes", "The torn painting and the break in of the book archives"; All the unbelievable incidents that happen at Shitamachi are somehow resolved by this somewhat eccentric family.