Seiichi Kurusu is the handsome eldest son in line to inherit a large company. After running into insecure dentist Nao Seto not once but twice coincidentally, Seiichi wonders if fate is at play. When Nao reveals that Seiichi actually reminds him of the man he's been unrequitedly in love with, Seiichi proposes a deal with him: for the length of time he receives his dental treatment from Nao, the two of them will date. Nao's tragic love history, combined with Seiichi's status as family heir and the impending countdown... can something good come from such a relationship?