The opening scene shows a young woman named Valentine (Kristen Stewart) on the phone. She is the personal assistant to Maria Enders (Juliette Binoche), a successful French-born international actress. On the phone, Valentine gets a call from someone claiming that Maria is holding up the proceedings of her divorce. Valentine claims that's nonsense, since Maria is the one who started the divorce in the first place. Valentine is seen having to juggle taking calls from two different cell phones.
Maria was a character called Nemesis in an X-Men film, but doesn't want to be in any sequels. She tells Valentine that she is sick of acting on wires in front of a green screen, so Valentine is able to get her out of the film and her name off of the IMDB (Internet Movie Database) page for the sequel, as people are constantly blogging about her in the film. Valentine tells her that her fans will be disappointed, but Maria doesn't care.
Maria and Valentine are heading to an event where Maria is to accept an award on someone else's behalf. That person is Wilhelm Melchior, a playwright and director, who casted Maria for a role in a play that propelled her to stardom. The play centers on the tempestuous relationship between a young girl and an older woman who is eventually driven to suicide.
Later, Valentine gets a call telling her that Wilhelm has passed away. This has now put the ceremony in a different light. The plan was for Maria and Valentine to go to the award ceremony, afterwards they were supposed to head out to Wilhelm's place in Sils Maria, which Maria still insists on going to.
In light of Wilhelm's passing, Maria finds out that the people behind the ceremony have invited actor Henryk Wald (Hanns Zischler). Maria really objects to this as she does not get along with Henryk. Maria considers not attending. She changes her mind once its announced that Henryk will accept the award if Maria does not attend. Those putting on the ceremony feel that Wilhelm wrote his work with Henryk in mind for different roles.
When they get to Maria's hotel room, Valentine finds out what Henryk is really like. Maria tells her that all Henryk wants is the spotlight. He is perverse, violent and hits women. Henryk wanted Maria, but disliked her when she wouldn't give in to his advances.
At the ceremony, Maria gets a call from Rosa, Wilhelm's widow, who tells her that she is glad that Maria is there to accept the award. Rosa also tells Maria what Wilhelm really thought of Henryk, saying the less you understand about him, the better and when you understand nothing about him, hes excellent. Rosa, breaking down in tears, tells Maria that she has to tell her something. It is inferred from Maria's responses that Wilhelm was diagnosed with something life-threatening, but instead of battling it, he instead swallowing something that led to his death.
At the event, Maria has a conversation with Henryk when he comes into the lounge area. Henryk tells her that he saw Wilhelm two weeks ago when they went fishing together. Maria tells him that she spent time with Wilhelm and Rosa six months ago. When Henryk says he knew about that, Maria tells him that she doesn't care that he knew.
After Henryk leaves, Maria reveals to Valentine that she had an affair with Henryk when they were shooting a movie together. Valentine says she figured so. Maria says that she was only 18 and that he took advantage of her. Henryk soon abandoned her and she didn't see him for 10 years. Afterwards, she hit it big and Henryk became interested in her again. This time, she didn't give in to his advances, which is why there's tension between the two.
At the hotel, Valentine arranges a meeting for Maria with Klaus Diesterweg (Lars Eidinger). He is a director planning a remake of Maloja Snake, except this time, he wants Maria to take the role of the older woman who is seduced by the younger woman. Maria tells Klaus that after all these years she still feels like that part is still who she is and doesn't feel right letting someone else take that role. Klaus tells her that Jo-Ann Ellis (Chloe Grace Moretz) will be playing the role of the younger woman. Klaus tells Maria that Jo-Ann has had a smaller career, having done a superhero film that just opened in the U.S., but that she's a lot more interesting than her profile suggests.
Klaus tells Maria that Jo-Ann admires her and is willing to opt out of her other commitments in order to do the play with Maria. Maria tells Klaus that, at the current moment, shes in the middle of a divorce and shes feeling alone and vulnerable. So, she doesn't feel like doing this movie. Klaus tells her that he will understand if Maria chooses not to do the movie, but tells her that it will be a missed opportunity, not just for her, but for Wilhelm.
Before he leaves, Maria tells Klaus that the actress, who played the older woman in the play, died a year later in a car accident and that she has always associated that with the suicide of her character in the play. Klaus says he remembers her, but remarks that she was a lousy actress who didn't understand a thing about the role. Klaus tells Maria that she should be grateful to her, since her lousy acting highlighted Maria's performance.
Maria talks with Henryk as they head back to the hotel. As she is about to go to her room, a drunk Maria gives Henryk her room number. Later on, she stands by her hotel phone, but gives up on him. She takes her tablet out and does a Google search on Jo-Ann.
A title card comes on the screen saying: PART TWO
Maria and Valentine are headed to Sils Maria. Maria tells Valentine that she shouldn't have said yes to Klaus. Valentine says that Klaus is a good director and the pay is good. Maria says she doesn't need the money.
Maria arrives at Wilhelm's house and is greeted by Rosa. Rosa tells her to stay as long as she wants. Rosa and Maria go hiking up the hills of Sils Maria. On another day, Rosa, Maria and Valentine watch one of Wilhelm's old films that he directed. Rosa soon leaves because of all the memories associated there. This leaves Maria and Valentine alone with the house.
Later at dinner, Maria and Valentine discuss Wilhelm, when Maria reveals that she was attracted to him, but didn't act on it because it would have ruined their working relationship. Valentine asks her if she was in love in him, Maria says of course she was.
After dinner, Valentine tells Maria about Jo-Ann's history. She tells her that there are numerous nude photos of her online and that her boyfriend broke up with her because she couldn't stop getting drunk and cheating on him with his friends in public. Valentine elaborates even more by saying that Jo-Ann went to her boyfriend's house with a gun and he threw her out of his house violently. Maria says that she doesn't sound anything like the way Klaus described her. Valentine continues on saying that Jo-Ann shot up her boyfriends place and was only stopped when the neighbors got involved and subdued her until the police arrived. Jo-Ann chose instead to go to rehab in order to get out of going to jail.
Valentine tells Maria that she respects Jo-Ann because shes not afraid to be herself. Maria says there's nothing cool in getting wasted and almost killing their boyfriend. Valentine says that Jo-Ann is probably her favorite actress, to which Maria says you mean more than me? Valentine says that she didn't mean it like that.
Upstairs in her room, Maria sees a YouTube video of Jo-Ann confronting a paparazzi cameraman who is following her. In the video, Jo-Ann gets out of the car she is in and throws her purse at the paparazzi's car and threatens to kill him unless he stops following her. She also watches Jo-Ann's DUI arrest video. A third video shows a press junket where Jo-Ann is asked questions about the upcoming play. A reporter asks Jo-Ann who is directing it. She responds Klaus. When they ask her if he has a last name, she responds Klaus. You know, THE Klaus. The reporters there begin laughing at Jo-Ann's response. Visibly embarrassed as to not knowing Klaus last name, Jo-Ann goes on a verbal rant telling the reporter that he needs to do his job and look him up.
The next day, Valentine helps Maria with her lines.
Later on Valentine and Maria go hiking to a lake, where they end up going skinny-dipping. Valentine says she will have to leave Maria for a few hours so she can go see her boyfriend, Burt. Maria says she'll be okay by herself for a few hours. She is also glad that Valentine has a boyfriend.
After Valentine leaves, Maria has a conversation with her agent and tells him that she wishes to be let out of her contract. She tells him that she has practiced her lines, but doesn't wish to do the part. Since she signed a contract, he tells her that if she doesn't, the producers will sue and it will go on for months and months. She asks for him to get her out of it, but he says that it is going to cost a lot. On her way back, Valentine drives through twisty mountain roads in the fog. At one point, she pulls over and throws up.
Sometime later, Maria and Valentine go to see Jo-Ann's newest 3D film. Afterwards, they go gambling. After they finish, they eat at the casino. During the meal, they talk about the film. Maria said that she could feel herself losing brain cells watching the movie. Valentine asks Maria if she found Jo-Ann amazing, because she did. Maria said that she played a dumb character. They both agree that she has a screen presence.
After having a few drinks during dinner, Valentine gets in the drivers seat and pulls out into a parked car. Maria tells her to hurry up and go. Valentine speeds out of the parking lot.
The next day, they both go hiking where they rehearse more of the play. Maria begins to see the play as phony. Valentine believes that plays can sometimes be more real than life itself. After lunch, Maria and Valentine both fall asleep on the mountain. Valentine wakes up and notices that it is almost dark. She wakes Maria up and tells her that its getting dark. Maria tells her that she knows a shortcut that will get them back faster.
As it gets dark, Valentine tells Maria that if she doesn't agree with the way she sees things, she doesn't have to keep her around. Maria says that she knows that. She likes having Valentine as her assistant. They eventually make their way to town and they take a bus back to the house.
The next day, they practice lines again. Maria still cannot see herself as the older woman character. Valentine tells her that she might be able to if she accepts the part like she did the younger character years ago. Valentine believes that it might be because she is reading the part to Maria. Valentine believes that she is uncomfortable reading the part and that it isn't helping Maria.
A few days later, Maria and Valentine go to a hotel to see Jo-Ann. Jo-Ann has come down to officially meet Maria. Jo-Ann is there with her boyfriend, Christopher Giles (Johnny Flynn). Jo-Ann tells Maria that after seeing a movie that she did with Harrison Ford, it inspired her to want to become an actress. Jo-Ann tells Maria that she knows that she wont be as good at the role as Maria was, but she hopes that she doesn't judge her too harshly. She also tells Maria that its incredibly brave of her to tackle the role of the older woman. Maria tells her that its just a job and that she'll be moving on when its over.
After the meeting, Valentine heads to the front desk when the attendant asks her if she is still interested in seeing the snake (this is apparently some kind of attraction up in the mountains of Sils Maria). Valentine says that she does. The man at the front desk gives her instructions on how to get there.
Maria tells Valentine that Jo-Ann was not like the girl that she was expecting. She says that she was really nice. Valentine tells Maria that Jo-Ann spent the whole evening flattering her and that's why she likes her. Maria says that has nothing to do with it. Valentine says of course not. Valentine tells Maria that Christopher is a well-known writer, who also happens to be married.
The next morning, Maria and Valentine are on their way to see the snake, but on the way there, they have an argument about the right path to get there. They get to the top of the mountain where Maria believes that she sees the snake. When she asks Valentine if that is it, she turns around and does not see her anywhere. Maria goes around and calls after her, to no avail. Valentine is gone without a trace.
After a short musical interlude, a title card flashes on the screen:
EPILOGUE, LONDON, A FEW WEEKS LATER
Maria is about to meet Klaus for dinner. On the way to dinner, Klaus tells Maria that Christopher's wife has attempted suicide after learning about her husbands affair. At dinner, Jo-Ann arrives and tells Klaus that Christopher is on his way. Klaus says that is a bad idea, because the paparazzi will be following him and will paint Jo-Ann and Christopher in a bad light. Christopher arrives at the restaurant.
Klaus gives Christopher his home address and tells him to meet them there. On the way out, Maria and Jo-Ann get into a limo. The paparazzi follow behind them.
At Klaus place, he says that the media is going to crucify Christopher. Jo-Ann says that she will take the blame, even if it means them painting her as a home wrecker. Klaus takes Maria home in a taxi.
The next day, Maria is looking over her lines for the play. Her new assistant arrives and asks her if she would be interested in doing a sci-fi film about a mutant. Maria says shell look at the script in a few days and get back to the director. Her new assistant asks Maria if she would like for her to help practice her lines, but Maria declines. It is clear that Maria misses Valentine.
On another day, the cast is doing one of the final dress rehearsals for the play. Afterwards, Maria asks Jo-Ann if she could do one scene a particular way. It is a scene where the younger woman leaves the older woman after everything is said and done. The way that Jo-Ann did the scene was that she just walked away from Maria's character. Maria tells Jo-Ann that when she played the character years ago, she made one final glance to the older woman character. Maria tells her that the audience thought it was more powerful. At that point, Jo-Ann says, at that point in the play, nobody cares about the older woman character. Jo-Ann says the character is washed-up. She tells Maria that she is talking about the character and not specifically about her. Through Maria's facial expressions, she does take it as Jo-Ann insulting her. Maria tells her that she still thinks it works, but Jo-Ann doesn't believe that it does. Maria chooses not to pursue it any further.
On opening night, Maria meets with the director of the mutant film. Maria says that she doesn't believe that the part works for her, even though he tells her that he wrote the part with Maria in mind. She believes that he wrote the part with a younger Maria in mind. Maria recommends Jo-Ann, but he doesn't want Jo-Ann in the part. He tells Maria that he dislikes this current era with stars like Jo-Ann and viral videos. He wants Maria for the part because she comes from a different era than Jo-Ann.
The final scene shows Maria on stage, in character, smoking. It is implied that she has become more like the older woman in the play.