On Valentine’s Day, Lin Xiao and his wife, Xu Mo, celebrate their seventh wedding anniversary. But Lin Xiao notices that his wife is acting strangely. Not only does Xu Mo have a QR code tattooed on her back, but she also has sexy lingerie in her bag.
All these suspicious signs make Lin Xiao suspect that his wife, Xu Mo, is cheating on him. The next day, Lin Xiao follows his wife and mistakenly believes that she is having sex with another man in a car. He follows Xu Mo to a hotel, determined to catch his wife in the act.
Yet every time Lin Xiao is about to catch Xu Mo cheating, she always manages to explain away all the strange things that happened before. This only makes Lin Xiao even more suspicious of his wife.