Role swap AU: Mutsumi Asano and her six siblings are ordinary civilians who have been struggling ever since their parents died under mysterious circumstances. Mutsumi spends a lot of her time visiting Taiyo Yozakura, a childhood friend who has been increasingly reclusive after his parents and brother died in an accident several years before. When a series of comedic errors leads to them accidentally getting married Yozakura-style, Mutsumi discovers that the Yozakuras are a family of super spies, and Taiyo was born to be the house head—except with the rest of his family gone, he's now the only Yozakura left standing. Now Mutsumi and her siblings band together to protect Taiyo from the Yozakura family's many enemies, using their unique talents and special interests to fend off kidnappers and assassins—the Asano siblings may not be superhuman spies, but they won't let anything stop them from protecting the newest member of their family!
