Plot summary

Set in 1989 Tokyo, Lucy Fly (Alicia Vikander), a young female expat, is suspected of murder when her friend Lily (Riley Keough) goes missing in the wake of a tumultuous love triangle with Teiji (Naoki Kobayashi). Lucy works as a translator at Sasagawa. Detective Oguchi (Ken Yamamura) picks up Lucy from her office after Lily's dead body is found a few days after she is reported missing. Lucy is questioned, but remains calm. She was the last person who saw Lily before she disappeared. Lucy says she went after Lily after she left home in the evening as she had something that belonged to her. But she says she never caught up with Lily.Lucy has been in Japan for 5 yrs and 2 months. No family in Japan. Father is an electrician and she has 7 brothers. She has no boyfriend in Japan. In flashback we see Lucy met Teiji, who is a photographer and who photographed her without her permission. They got talking and eventually went on a date. Teiji takes more photos of her and they share a shelter when there is a mild earthquake. Lucy takes violin lessons. Lucy met Teiji first. She was then introduced to Lily, who was a new joiner at her company. Lucy was shy and introvert, while Lily is loud and extroverted. Bob (Jack Huston) is Lucy's friend who introduced Lily to her.Lucy has a work friend named Natsuko (Kiki Sukezane), to whom she tells about how she is dating Teiji. Lucy and Teiji have sex after they learn about each other macabre fascination with death. Lucy takes Lily apartment hunting and they start spending more time with each other. She tells Lily about Teiji. Lucy finds out that Lily was a trained nurse back in DC. She is oddly intimidated by that. Lily suggests that she wants to meet Teiji. Lucy asks Teiji to sell his photos, but he is very cold to the idea and brushes her off. Lucy goes back to his studio and looks at his photograph folder to find that Teiji has taken photos of one more woman before her. Teiji is offended and Lucy apologizes profusely after Teiji tells her that this woman Sachi, was his muse before Lucy.Lucy takes Lily to the noodle place where Teiji works. Lily then starts spending nights over at Lucy's and observes that Teiji doesn't come to Lucy's apartment. Lucy invites Lily to an art festival where Bob is playing with his band. Bob thought he and Lily had a thing, but he tells Lucy that Lily gave him all the signals but then lost interest in him. Lucy sees Lily dancing with Teiji at the festival. Then the 3 go together for a picnic and that night they end up having a 3 threesome at Lucy's place. But in reality Lily and Teiji had sex. The next day Lucy gets really mad at Lily and Teiji when they leave her behind (she was sleeping) to go for some sightseeing. Lucy is really angry and the next day she finds Teiji taking photos of Lily.Lily comes over to apologize and we see Lucy running after Lily in the rain, and the flashback ends. Lucy admits to Oguchi that she murdered Lily, but the body found by the police is not Lily's. Lucy admits that she lied about killing Lily but said she wanted to kill her. Lucy is released. She goes to Teiji's studio and once again breaks into his cabinet to find Lily's folder and finds the last photo, which is of Lily dead and her head smashed in. Lucy takes the photo to Oguchi, but cant find him at the station. She goes back home to find Teiji waiting for her. Teiji wants Lucy to run away with him, when she refuses, he attacks her. Lucy kills Teiji with a glass vase.