A college reunion that had lasted twenty years allowed Chen Mo, a middle-aged deputy director of a state-owned enterprise trapped in a dull and lukewarm marriage, to reunite with Bai Yueguang Su Juan, whom he had fallen in love with when he was young. Looking back, twenty years of dusty heartbeats suddenly awakened. The regrets of missing out when they were young and the depression of middle-aged marriages were completely overturned when they looked at each other and tested on WeChat. The two people, who had already started their own families and whose edges had been smoothed by life, could not restrain the hot old feelings in their hearts, crossed the boundary between morality and reality, and set up a secret date. The love that had been dormant for twenty years rekindled, and taboo feelings spread wantonly. They were deeply pulled by throbbing and guilt, and an old love entanglement that was destined to subvert each other's lives completely kicked off.