26-year-old Rino graduated from junior college and started working at a major cosmetics company. Through a friend's introduction, she began dating a man employed at a top-tier foreign company, and after four years they married. They have one daughter, and she currently lives as a full-time housewife. Her husband's career is going well, and there are no complaints about her family life—but precisely because of this stability, a vague sense of emptiness has begun to stir deep within her heart. This is the story of how she ends up going on a one-night, two-day hot spring trip with a man she met through a dating app. Seeking excitement beyond her daily routine, she sets off on a journey to fill the emotional void inside her.