Max Caulfield and her "partner in crime", Chloe Price, start an investigation into the mysteries surrounding Blackwell students Kate Marsh and Rachel Amber. As they make headway, Chloe discovers that even those close to her have secrets. A new rewind power presents itself to Max, and its use has devastating consequences.
Max wakes up suddenly in her dorm room on the night Kate Marsh attempted suicide, still reeling from the events of the day. She receives a text message from Chloe who wants to meet her in front of the campus, prompting Max to leave her room to go and meet her. If Max decides to speak to Taylor Christensen in the communal bathroom before leaving the dormitory, she will learn that Victoria Chase had sneaked out of her dorm room past curfew and told Taylor not to tell anyone.
When Chloe makes her presence known to Max outside the main building, she presents a set of keys to Blackwell that she has stolen from her step-father. They decide to start their investigation by breaking into the Principal's office to look for answers. However, they soon discover that the key to the Principal's office is not included in the set. Chloe attempts to pick the lock, but after failed attempts to open the door, Max contacts Warren Graham to ask him how to build a pipe bomb. Max gathers the necessary materials from the Science and Art labs and blows the lock, creating a way in but accidentally triggering an alarm.
Max enters the office and rewinds to the point before the explosion to unlock the door for Chloe. While inside the office, Max looks for the school's files on Kate, Nathan Prescott, Rachel Amber, Chloe, Warren and herself, while Chloe investigates the Principal's computer. Shortly after, Chloe finds evidence of a cover-up concerning Nathan's grades, David Madsen's movements, and a disturbing scribble where "Rachel in the Dark Room" is written repeatedly.
Now that they have the information they need, they decide to leave, but not before Chloe opens a drawer of the Principal's desk to discover five thousand dollars in an envelope marked "handicapped fund". Chloe wants to steal the money so that she can finally repay Frank Bowers, and Max has the option of allowing her to do so. As they leave the office together, with or without the money, Chloe has a sudden change of plan: a late-night swim in Blackwell's pool.
They gain access to the swimming pool building and find their way to the pool through either the boys' or girls' locker room. The girls reminisce about their lives as they play around in the pool, and Chloe tells Max how she thinks Max's power is changing her. As they decide to leave, they hear Blackwell security enter the pool building and try to find a place to hide. (If David Madsen wasn't fired earlier that day, he will be heading up the security team.) Max and Chloe manage to avoid security and escape the building, running towards the parking lot where Chloe left her truck. Now that they are "Blackwell fugitives", Chloe suggests that Max crash at her place.
She spends the night at Chloe's house. When she wakes, she discovers that her clothes still reek like a "chlorine factory", so Chloe tells Max to look in her wardrobe to try on the clothes that Rachel left behind. When Max isn't sure that they would suit her style, Chloe encourages her by telling her to stop second-guessing herself and to let her "inner punk-rock girl come out". She tells Max that she can afford to take chances, whenever and whatever she wants to try. As an example, she dares and then double-dares Max to kiss her. Max has the option to kiss Chloe before she leaves Chloe to her thoughts and heads downstairs for breakfast.
Once downstairs, Max helps Joyce Price prepare the family breakfast before sitting down at the table to eat as she waits for Chloe to join them. Joyce walks over to the table with the Price Family photo album and sits opposite Max to go through the photographs with her. They reminisce about the past, and Max expresses her sympathy over what happened to Chloe's father. Just before Chloe enters the room, Joyce hands Max a photo of her and Chloe that had been taken on the day William died in 2008, saying, "This was the last time I ever saw Chloe truly happy."
Chloe distracts Joyce by picking an argument with her while Max steals away to investigate the garage. Finding that David's laptop is locked, Max looks for password clues in the garage and gains access to his computer. She discovers files on Rachel, Kate, and herself, as well as the discovery that Rachel was romantically involved with Frank.
Max returns to the living room with answers, but while she tells Chloe what she found, David walks into the house. When he accuses students from Blackwell of the vandalism, an argument breaks out between Chloe and David. Max and Chloe take the opportunity to reveal that David has been spying on students. Joyce demands he leave students and Max alone. Max will then be able to side with either David or Chloe.
Before Max can tell Chloe about her discovery, David returns home and relays news of the break-in at Blackwell the night before to his wife. As his attention turns towards Max, he makes a derogatory comment about her dressing in Rachel clothes, which starts a quarrel that leads to Max and Chloe divulging his student surveillance activities in front of Joyce, who is very concerned by this. As things escalate, Max can choose to side with either David or Chloe.
After the argument, Max and Chloe leave the house. In Chloe's truck, Max finally tells her that she had seen evidence of Rachel and Frank being more than friends, but Chloe doesn't believe her. Max suggests they break into Frank's RV so they can be proved wrong about this and to see what other evidence he may have in there. They head to the Two Whales Diner where Frank's RV is found to be parked. Knowing that they will need the keys to the RV, Max goes into the diner with the intention of using her rewind power to get Frank to hand over his keys unknowingly. During this process, Max learns that Frank rescued his dog and has a favourite photograph of Rachel Amber, so she uses this information on Frank to get him to take out his keys. As Max snatches his keys from the table, she quickly rewinds time so that Frank is unaware that he no longer has them. She heads back to the RV, and Chloe hands her a bone to throw as she opens the RV door so that Frank's dog, Pompidou, doesn't attack them.
Once inside Frank's RV, Max finds an account book with proof that Frank and Rachel were involved romantically with each other. As soon as she shows this to Chloe, Chloe flies into a rage and thinks that Rachel betrayed her, saying, "I can't believe she was banging Frank! Rachel straight up lied to my face!" During the drive back to Blackwell, a tearful Chloe takes her anger out on Max and everyone who is or ever was close to her.
Chloe drops Max off at Blackwell without saying a word to Max when she exits the truck, and Max returns to her dormitory, saddened by Chloe's outburst. She sits on her bed in her dorm room and studies the photograph that Joyce had given her that morning. As she stares down at the image of her and Chloe, it starts to emit voices. Confused, she focuses on the photograph and suddenly finds herself in 2008 inside her 13-year-old body at the moment the photograph was taken. Knowing that this was the day that William was killed in a car accident, Max hides his keys and talks him into taking the bus instead. Max rewrites history.
Suddenly, Max is back in the present time in her 18-year-old self. She finds herself sitting on the main campus lawn at Blackwell Academy and discovers that she is a member of the Vortex Club and that Victoria is now her friend. She spies Warren nearby, who now appears to be dating Stella Hill. Suddenly remembering Chloe, she quickly runs off campus grounds to catch the school bus and see what has become of Chloe. She notices that the bus driver is David Madsen. As she arrives at the Price Household, William opens the door to her. He is pleased to see her and shouts for Chloe to tell her she has a visitor. As Chloe approaches, Max is horrified to discover that her best friend is now in a wheelchair... and quadriplegic.