All Our Yesterdays
is a 2013 young adult science fiction thriller by Cristin Terrill.
The story opens with a girl named Em in a prison cell. A boy named Finn is in the cell next to hers, and they can hear each other. When her food tray arrives, Em uses the utensils to open the drain and discovers a note written in her handwriting, though she’s never seen it before. The note details a list of instructions from previous versions of herself, with the final instruction intended for her, the most current version. It reads, “You have to kill him.” Em realizes she has escaped from the cell many times before, using time travel technology to repeat her timeline. Em and Finn are imprisoned by an evil, power-hungry man known only as The Doctor, who was once her friend, James. He’s torturing them for the location of documents they stole. The Doctor invented Cassandra, a time travel machine, and the result of that invention is a world torn by warfare.
Em and Finn escape their cells and travel back in time.
In the past, a girl named Marina waits for her neighbor, James Shaw, to return home from school. James is handsome and brilliant, and Marina is in love with him, but he has never shown any interest in her beyond friendship. She visits James but leaves when his friend Finn shows up, as she dislikes Finn. James later invites her to a family event, and Marina is determined to make him notice her as a girl. At the event, Marina is just about to invite James home with her when James’s brother Nate is suddenly shot. Marina and Finn follow the family to the hospital.
Em and Finn arrive in the past. They travel to the hospital; they know where their younger selves will be because Em is actually an older Marina. Em shoots at James when he appears but fails to kill him. Em and Finn go into hiding.
Marina witnessed the shooting and tells everyone that the attackers looked like her and Finn, but no one believes her. She, James, and Finn go to Finn’s house for some rest; Em and Future Finn follow. Em has a chance to kill James but hesitates because of her past self.
At the hospital, Nate wakes and is able to signal to Marina, indicating that his shooting is somehow connected to James. The police inform them that the shooters were actually two young boys. Marina urges James to go to Connecticut to conduct his own investigation, as Nate indicated. The three friends drive to the Shaw’s Connecticut house, where they discover an email from head investigator Chris Richter about Nate and James, as well as files about James and his scientific research into time travel. While driving back, they learn that Nate has died, and they stop a hotel for the night.
When Marina and Finn go to get food, Em and Future Finn enter the hotel room and confront James. Future Finn tells James that he does successfully invent time travel, but James doesn’t believe them. They tell James point blank they’ve come to kill him, but Marina and Finn return and save him. Em and Future Finn escape out the window, and Marina, Finn, and James flee.
Future Finn is upset to learn that Em let James escape because she still loves him; he loves Em. Em has a flashback and admits she loves Finn, but still has strong feelings for James.
James, Finn, and Marina arrange a meeting with Richter, who implies that Nate was killed because he knew too much. He invites James to join the group so they can fund his time travel research, then tells him they have Nate’s attackers in custody. James is tempted by the offer, and Em, observing the meeting, realizes she has actually steered James toward becoming The Doctor. Finn is horrified and walks away. Marina realizes that James never really loved her, and leaves as well. Em follows James out of the restaurant and tries to shoot him, but the gun jams. James gets in a car with Richter, and then Em is drugged.
The Doctor intends to kill Finn and Marina in the past, reasoning that if he does, they won’t be around to cause trouble in the future. While Marina and Finn are driving, The Doctor attacks. They flee the car as Future Finn arrives and fights The Doctor. The Doctor defeats Finn and tasers Marina.
Meanwhile, Em follows Richter and James to a fake restaurant. She gets inside and finds James willing to talk to her. She tells him what the future brings and then passes out from another flashback. Em comes back to herself and pulls out the gun; she and James struggle with the weapon. James takes the gun, but Em receives a phone call. The Doctor tells her to bring James to him or he’ll hurt Marina and Finn, who he has tied up in a house. James and Em agree to a truce and, together with Future Finn, they go to save their past selves.
At the house, Em is captured by The Doctor. Finn is shot, and Future Finn disappears. Em tells James that he killed his own brother, sending soldiers from the future to the past because killing Nate sped up Cassandra’s creation. The two versions of James fight. James wins and kills The Doctor—both The Doctor and Em fade away.
Marina wakes to Nate knocking on her door to tell her that his brother James has killed himself.