Two young lovers in a happy relationship are forced to break apart by their families, but they both decide to make a promise in secret. That is, to reunite once again as adults and save themselves for marriage.

Years pass, and the boy named Kwan reunites with his former lover once again, Annika, the same pure-hearted goody two shoes girl he used to know, all grown up to be an elegant young lady.

Unfortunately for Kwan, he had broken his promise over the years and turned into a devious bad boy who indulges in any pleasure he desires. In order to make up for it, he is forced to make another promise to abstain from all vices.

But in the island of UniverCity, where all sorts of dicey temptations grow rampant, the journey surely won’t be easy.