When Cecilia’s abusive ex takes his own life and leaves her his fortune, she suspects his death was a hoax. As a series of coincidences turn lethal, Cecilia works to prove that she is being hunted by someone nobody can see.
Cecilia Kass escapes from her abusive boyfriend, optics pioneer Adrian Griffin, with the help of her sister Emily and childhood friend James Lanier. Cecilia is terrified to go outside, thinking Adrian will find her, but she receives news that Adrian has committed suicide and left her a $5 million fortune on the condition that she proves herself to be mentally competent.
Cecilia is soon terrorized by an invisible force, which she believes to be Adrian still alive and having found a way to become invisible. This causes a strain between her and Emily and James since Adrian wrote a horrible email to Emily and struck James’s daughter Sydney, making them believe it was all Cecilia. Her theory is proven correct when she goes to his house and finds a machine and suit he developed to turn people invisible. When she tries to prove it to Emily, the Invisible Man kills her in public and makes it look like Cecilia did it.
Cecilia is locked up in a psych ward and finds out she’s pregnant with Adrian’s child. After managing to expose him and escape, he kills several guards before threatening to go kill Sydney. James gets beaten by the Invisible Man to protect Sydney, but Cecilia comes in the nick of time and sprays him with a fire extinguisher before shooting him dead. She unmasks him to find Adrian’s brother Tom having been wearing the suit, with police finding Adrian alive and seemingly kidnapped by Tom, but Cecilia knows this was his plan all along.
Cecilia goes to Adrian’s house under the guise that she can get him to incriminate himself, with James listening through a wire. She instead uses a suit she stole from him to become invisible and slash his throat, making it look like a suicide for the security camera. Cecilia leaves the house, now free from terror.
Trapped in a violent, controlling relationship with wealthy optics engineer and businessman Adrian Griffin, Cecilia Kass one night drugs him with diazepam and escapes their home with help from her sister Emily.
Cecilia hides out with childhood friend Detective James Lanier and his teenage daughter Sydney. Adrian seemingly commits suicide and leaves Cecilia $5 million in his will, handled by his lawyer brother Tom. Cecilia suspects another presence in the house after several strange events and calls for James but he assures her she is just traumatized. During a job interview, she faints after finding her work portfolio’s contents removed. The doctor says they found high levels of diazepam in her system. She finds the same bottle she drugged Adrian with, which she dropped during her escape, in her bathroom.
Cecilia arranges a meeting with Tom and James, insisting that Adrian faked his death and used his optics expertise to become invisible in order to torment her, but gets rebuffed. Sydney is hit by an unseen force, leading her and James to assume Cecilia did it. She tries a number of tactics to catch the figure. After finding Adrian’s old phone and covering the figure with paint, she ends up in a violent struggle before escaping to Adrian’s home to investigate. In his lab, she finds a suit that confirms her suspicions. The invisible figure attacks again so she flees and contacts Emily. The pair meet in a restaurant but the invisible figure slits Emily’s throat and places the knife in Cecilia’s hand, framing her for the crime.
Remanded to a mental hospital while she awaits trial, a staffer informs Cecilia that she is pregnant. Tom offers to get her charges dropped if she agrees to “return to him” and raise the child, implying that he helped his brother stage his suicide while revealing Adrian tampered with her birth control to ensure she became pregnant. Cecilia refuses and steals a pen from his briefcase. That night, she uses the pen to pretend to commit suicide to draw the invisible figure out. When the figure tries to stop her, she stabs him repeatedly, causing the suit to malfunction. The security team arrives but the figure incapacitates them before fleeing the hospital with Cecilia in pursuit. Promising not to harm her because of her pregnancy, the figure instead threatens to attack those she loves.
Cecilia races to James’ house, where she finds the figure attacking him and Sydney. She manages to shoot him but when she unmasks him, it is Tom in the suit. Police find a captive Adrian alive at his house, tied up and claiming Tom held him prisoner. Cecilia disputes this, insisting the brothers must have shared the suit, with Adrian sending Tom to the house knowing what would happen.
In an attempt to get Adrian to confess, she meets him at his house while James listens on a wire. She agrees to mend their relationship but only if he confesses to being the figure. Adrian insists Tom did kidnap him, claiming the experience changed his outlook on life and how he treated her. When she cries, Adrian alludes to his abuse, using similar phrasing to that of the figure. Smiling, Cecilia departs to use the restroom. Moments later, the security camera captures Adrian seemingly committing suicide. Cecilia returns and apparently distraught, calls the police. Out of the camera’s sight however, she taunts Adrian after retrieving the spare suit she used to kill him.
When James arrives, she confirms what the camera saw. He spots the suit in her bag but allows her to leave. Relieved that she’s finally free of Adrian, Cecilia leaves with the suit.
The film opens with Cecilia Kass (Elisabeth Moss) waking up in the middle of the night as she prepares to escape from her abusive boyfriend Adrian Griffin (Oliver Jackson-Cohen). She drugged him with Diazepam and quietly makes her way out by retrieving her belongings and turning off the alarms to avoid waking Adrian up, all while monitoring him through a camera on her phone. As she gets outside, Cecilia sees Adrian’s dog Zeus coming out. She removes his shock collar, but he accidentally bumps into a car, setting off the alarm and forcing Cecilia to make a run for it as she knows Adrian is waking up. She runs out from his estate and runs into the street to meet her sister Emily (Harriet Dyer). As she gets in the car, Adrian comes running and demands that Cecilia open the door, even smashing the window of Emily’s car before she drives them away. Adrian then finds the bottle of Diazepam that Cecilia dropped.
Two weeks pass, and Cecilia has been staying with childhood friend, Detective James Lanier (Aldis Hodge) and his daughter Sydney (Storm Reid). Cecilia has been too frightened to set foot outside the house for fear that Adrian will find her. James tried to convince her to go outside, and she makes it to the mailbox before being startled by a jogger that she thinks is Adrian, causing her to run back into the house. Emily then comes to visit, which Cecilia doesn’t like since Adrian knows where she lives and thinks he may have followed her to find Cecilia. Emily then reveals a news article to Cecilia stating that Adrian has committed suicide.
Cecilia sits in shock as she processes the news. She explains to Emily and James just how abusive and controlling Adrian was toward her, and how he wanted a baby, but Cecilia knew that would only mean she couldn’t get away from him, so she started taking birth control without him knowing.
Cecilia and Emily meet with Tom (Michael Dorman), Adrian’s brother and lawyer who presents them with his will that states he left a $5 million fortune to Cecilia, which she can have on the condition that she proves to be mentally competent and also not commit criminal charges. With this news, Cecilia gifts James a new ladder and opens an account for Sydney’s college tuition. The two are extremely grateful.
At night, Cecilia starts to feel an unnerving sensation, as though someone is in the room with her. She walks outside the room to look for James and Sydney, but they are not there. She walks outside in the cold, where someone’s breath is shown beside her.
In the morning, Cecilia cooks breakfast for James and Sydney, but when she has her back turned, an invisible force drops the knife from the counter and then turns up the heat on the stove, causing a small fire that Sydney quickly puts out.
Later that night, Cecilia is sleeping in bed with Sydney. The invisible force pulls the covers off them and quietly takes pictures of them. Cecilia wakes up and tries to retrieve the cover, but then sees what look like footprints standing on the covers. They start slowly moving toward her until she feels a push and calls for James. She claims someone is in the room with her, but James and Sydney see nobody else.
Cecilia later goes for an interview at an architectural firm, but when she tries to present her work, she finds that her bag has been completely emptied. She starts having a small panic attack before fainting. Later, Cecilia gets bloodwork done and is told that there were high traces of Diazepam in her system. To her horror, she finds the bottle she dropped in James’s bathroom with Adrian’s bloody fingerprints on them.
Cecilia and James go to talk to Tom, presenting him with the bottle and Cecilia claiming that Adrian is making good on his previous threat to her about finding her wherever she goes, and him leaving her a sign. Knowing that Adrian was famous for being a pioneer in the optics field, Cecilia believes that he has found a way to turn himself invisible. Tom disagrees since he has an urn with Adrian’s ashes and also presents her with crime scene photos to confirm that Adrian slashed his wrists.
Cecilia later goes to visit Emily, who is not happy to see her due to an email she received from Cecilia’s account. Although she insists she didn’t write it, Emily doesn’t believe her claims that Adrian is doing this, and sends her sister away. Cecilia goes home to read the email and sees that someone (Adrian?) wrote a scathing message to Emily, making it seem like Cecilia wants nothing to do with her and wishing that she died instead of Adrian.
Sydney comes in and finds Cecilia crying over the email. When she offers to help her out, the invisible force strikes Sydney in the face, making her think that Cecilia hit her. James comes in and takes Sydney away, despite Cecilia pleading and saying it wasn’t her. After they leave, Cecilia dares Adrian to reveal himself. She spills coffee grounds on the floor and stays in the bedroom, waiting for him to reveal himself. She then tries calling Adrian’s cell phone, which she can hear ringing in the attic. She goes up there to find it, and an unknown number writing “SURPRISE.” Before going back downstairs, Cecilia figures the Invisible Man is there, so she spills paint on him to reveal him. After making her way back downstairs, she sees the kitchen sink running and sees he washed the paint off. After grabbing a knife, the Invisible Man grabs Cecilia, choking and throwing her across the room. She fights back and manages to escape the house.
Cecilia calls for an Uber, which takes her to Adrian’s house. She makes her way inside and goes into his basement, where she finds a machine and suit that is covered with cameras and can turn invisible, which explains how Adrian has been haunting her. As she tries to get out with the suit, she hides in the closet and sees another pair of invisible footprints. She pushes the Invisible Man away and runs back to the car.
Cecilia arranges a meeting with Emily at a restaurant. As she begins to try and explain herself and what she discovered about Adrian, a knife floats between them. The Invisible Man slashes Emily’s throat and places the knife in a stunned Cecilia’s hand. The other patrons freak out as they see Emily dead and Cecilia holding the murder weapon. Police arrive and quickly arrest her. She is carried into a psych ward screaming that Adrian killed Emily until she is strapped down and sedated. She knows Adrian is in the room with her, confirmed when she hears a voice tauntingly saying “Surprise.”
Cecilia is tested and interrogated for allegedly killing Emily. Although she tries to explain herself, she fears Adrian is in the room with them to listen to what she says. The doctors also reveal that Cecilia is pregnant. Tom comes to visit her to offer a deal to make this go away. Either she splits her inheritance with him, or she returns to Adrian with the baby, as Tom is aware that he’s alive and that Adrian knew Cecilia took birth control, swapping it out with something else. Cecilia pushes Tom’s belongings off the table, giving her a chance to grab one of his quill pens and a piece of sticky material. She then overhears on the news that it will rain in a few days.
Days later, it is pouring outside. Cecilia waits for an opportunity and grabs the pen she hid. She turns on the shower and says out loud that she is not going to let Adrian have the baby. She begins to cut into her wrist with the pen before the Invisible Man grabs her. Cecilia stabs him with the pen, causing the suit to malfunction. A guard enters, and the Invisible Man tases him. Cecilia tries to run as more guards come, but the Invisible Man brutally kills them all. She grabs a gun and makes her way outside in the rain, where he takes down another guard. The two confront each other, with the Invisible Man threatening to kill Sydney. Cecilia takes a car and calls James to head back to the house.
The Invisible Man arrives and starts to attack Sydney, but James arrives and ends up getting beaten mercilessly. Cecilia arrives and sprays him with the fire extinguisher before shooting him four times. He stumbles until he collapses dead. Cecilia unmasks him to reveal Tom having been wearing the suit. Meanwhile, a SWAT team storms Adrian’s house to find him alive and apparently kidnapped by Tom.
Cecilia is vindicated due to police believing Adrian was a pawn in Tom’s personal scheme, but she knows the truth and says that this was Adrian’s plan all along, including setting up his brother to take the fall for him. Cecilia later gets in touch with Adrian and sets up a meeting.
Cecilia goes to Adrian’s house for a dinner he set up. James is outside listening in, expecting Cecilia to get Adrian to incriminate himself. They sit in full view of the security camera. She tells him he can’t have the baby, but Adrian puts on his superficial charm to seem good toward her. She excuses herself to the bathroom. Moments later, as Adrian sits alone, the knife he is holding goes up, and his throat is slashed. Cecilia comes back out and pretends to cry for the camera, but it’s clear that she turned the tables on Adrian by using his suit to kill him. James rushes to the scene, but despite seeing the suit in her bag, Cecilia remains firm that Adrian committed suicide, and James appears to have no choice but to accept that story. Cecilia leaves with Zeus, now finally a free woman.