Frances (Chloe Grace Moretz) is a simple and kind female college student. One day, on the subway, Frances picked up a handbag and found the address on the note in the handbag. Frances knocked on the door of Greta (Isabelle Huppert). Greta thanked Frances for her kindness. During the conversation, Frances learned that she was a widow who lived in loneliness all day, and immediately felt pity for her. In this way, the movement between Frances and Greta became more frequent, and the relationship between the two became more and more warm, and they were even regarded as mother and daughter. One day, Frances accidentally found a lot of bags of the same style as the handbags she had picked up at Greta's house. There was a note with an address in each bag, which made Frances begin to realize that she seemed to have fallen into the trap set by Greta.