Arisu, who works at a major trading company, and her boss Yuichi have been drawn to each other, continuing a secret affair. While they maintain a professional relationship at work, privately they harbor intense feelings. However, since Yuichi is married, life always returns to normal after their trysts—until now. They've never spent an entire night together until this moment: their first hot spring trip. At a secluded, quiet inn, their bond deepens, igniting a passionate relationship unlike anything before. Removed from daily life, sharing time alone, new emotions awaken, opening the possibility of a love that transcends the label of infidelity.