The main character is Tsuki Hayakawa, the daughter of Takeru, Yui's younger brother from Ashi-Girl. One day, the time machine built by Takeru is activated for the first time in 15 years, and Tama-hime, the younger sister of Hisanaga, is brought back from the Edo period. Tama-hime tells Tsuki that she had to give up on the man she loves and will soon be married into the family of a feudal lord. Tsuki, who is an inventor prone to doing "outrageous things" just like her father, decides makes a big move...