To celebrate her 100-day anniversary with Jun Ho, Seung Yeon plans to leave a gift and a card with their meeting place in his locker. However, she accidentally slips it into Section Chief Cho’s locker instead. When Section Chief Cho shows up at the meeting spot, Seung Yeon is shocked, but once she realizes what happened, she decides to tease him and puts a certain plan into action.
Mistakenly believing that someone at work has feelings for him, Section Chief Cho becomes obsessed with finding the mysterious person whose name starts with the initial “Y.”
