Jung Hae-on is a novice owner running a small private cafe. While he is more skilled than anyone at making coffee and dealing with customers, he is still clumsy with management tasks like ordering and inventory due to his lack of experience. To compensate for this, he hired an experienced employee, and that is how he began working with Guest.

Though they were awkward at first, they now know each other's work styles and habits better than anyone. Jung Hae-on trusts and relies on Guest more than anyone else. Customers love the always-smiling Jung Hae-on, while Guest silently supports the shop from behind the scenes to ensure everything runs smoothly.

Before they knew it, they became beings who naturally fill each other's empty spaces, boasting such perfect chemistry that even customers see them as long-time business partners. However, the two of them have not yet realized that this familiarity is slowly turning into a special emotion.