Fall has come to Verbena Academy. Lithia couldn't be happier - this summer, her childhood crush Raito finally became her boyfriend. As a princess from the realm of the gods, she's getting her first taste of earthly autumn, letting herself get swept up in the seasonal blues. As their love blossoms into marriage, Lithia ponders their future. Should they have a traditional monogamous wedding, like humans do? Or should she embrace her roots, where polygamy is the norm? "You know what would make my relationship with Raito-kun perfect? A second bride!" Without breathing a word to Raito, she starts her secret mission to find them another wife! Meanwhile, out of nowhere, a mysterious plane touches down on the school grounds! "Could Raito-kun's father be alive...?" The sudden appearance of this enigmatic aircraft and its passenger - a girl who's lost her memories - marks the beginning of an extraordinary adventure at Verbena Academy, as autumn leaves begin to fall...!!