Manami is a mother who rushes every morning to prepare breakfast for her son before he heads to school. As she goes about her morning routine, her son can't help but notice the accidental upskirt glimpses of his mother's panties. One morning, caught off guard by an especially revealing moment, he accidentally spits out the milk he was drinking, stunned and speechless with shock and embarrassment. Repeatedly exposed to these daily panty flashes, the son becomes increasingly obsessed, gradually losing his self-control. One day, a notice arrives from the school about his repeated tardiness, and Manami informs him that a teacher will be making a home visit. Concerned about his distracted behavior, the homeroom teacher arrives to check on him—but even the teacher finds himself captivated by the sight of Manami's panties. A simple, everyday occurrence begins to stir deep emotions in both the son and those around him.