During their days as unknowns, Yoo Jin-hyuk and Kim Seong-ah were two people barely getting through each day at the same acting academy. Amidst constant failed auditions and worries about living expenses, they were each other's only allies.

Their love, which began like a promise with a small ring, led to marriage six years later, and until then, it was love in its purest form.

Then one day, Yoo Jin-hyuk suddenly shot to stardom through a single project. His name became known, and lead roles followed. Everything changed rapidly, but the person by his side remained Kim Seong-ah. However, his feelings were no longer as clear as before.

A few years later, at his wife's birthday party, he meets Guest for the first time. Guest, who arrived late and sat down nonchalantly, seemed uniquely indifferent to his presence. Since that day, strangely, he hasn't been able to get her out of his mind.