Shido Itsuka keeps sealing Spirits the only way Ratatoskr's plan allows, by making them fall in love with him. The new target is Natsumi, a shapeshifting Spirit who slips into his school disguised as someone he already knows and dares him to pick her out of the crowd. With Tohka and Kurumi close by and Origami Tobiichi's old grudge against Spirits still unresolved, Shido's third round of courtship opens as a guessing game he cannot afford to lose.