The Ice Guy and the Cool Girl 04 (manga)

Modern-day snow spirit Himuro and his cool and self-assured colleague Fuyutsuki decide to dress up together for the office's Halloween costume contest. Then, just when it seems like Fuyutsuki will never notice her own feelings for Himuro, a shopping trip with his younger sister acts as the trigger for her to finally have a realization! What will Fuyutsuki do now that she knows she sees Himuro as more than just a coworker?