For his wife's high school reunion, the husband heads to her hometown in Nagano. In truth, his real purpose is to reunite with his stepmother. While his wife is occupied with reunion events, the husband seizes the chance to be alone with her and finally crosses the line, becoming intimately involved with his stepmother. Amidst the stepmother's pent-up desires, the husband overcomes his self-restraint, beginning a new secret relationship. Watch how this affair transforms the bond between husband and wife.