After divorcing, her son started working but due to a long commute, he continued living at home, spending most weekends isolated indoors. Worried about him, Orié decides to take her son on a hot spring trip. Alone together, suppressed emotions begin to surface between mother and son. Though physical contact is forbidden, they find themselves drawn to each other and agree to spend this day as lovers. As he sucks her nipples and she takes his cock into her mouth, overwhelming pleasure clouds her judgment. Losing all reason, they repeatedly indulge in forbidden intercourse. Their fleeting bond formed in the hot springs becomes a journey etched deeply into their hearts.