In a parallel universe of Japan, set during the bubble economy period, resides a detective father, a chatty mother, a conceited sister, and a troubled man. Following his own scheme, Ryosuke Takagi set off on a journey of plagiarism; however, after a family gathering, he took on his mother's assignment. Mieko stated, "There's something I need to ask you." Consequently, Ryosuke acquired a tracker, which was located on his younger sister Takashiro Ryōno's backpack.