For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
1998
Act I, a.k.a. the setup or exposition, provides us with all the information we need to read the story and understand it. Think: who, what, where, when, and why—with the occasional how thrown in for flavor.
In 1998, Renfrew and Markham team up to convince Ian Peterson to get funding for Renfrew's experiment. The experiment will send messages to the past using tachyons, hypothetical faster-than-light particles. Peterson gets the funding, and Renfrew starts sending those messages.
The inciting incident, the moment that changes life for the characters and pushes things into Act II, is when Peterson discovers a message that has been waiting for him for more than thirty years in a safety deposit box. Clearly the messages are getting through, but with the world still deteriorating around them, are they having any affect? To be continued… in Act II.
1962-63
Professor Gordon Bernstein and graduate student Albert Cooper pick up some odd interference in their experiment. After trying to find the source of the information, they decipher it using Morse code and find what looks like a message.
Gordon asks fellow biology professor Michael Ramsey and astronomer Saul Shriffer for help deciphering aspects of the message. While Renfrew keeps it hush-hush, Shriffer goes public with the data, strongly hinting that he believes the message has an extraterrestrial origin.
The backlash from Shriffer's public campaign smacks Gordon in the career. The turning point comes when Gordon is openly ridiculed at his colloquium and Professor Lakin dismisses Gordon's findings completely.
Act II
1998
Renfrew continues to send messages to the past while working later hours and straining his relationship with his wife, Marjorie. Markham also keeps on keeping on, trying to figure out if the experiment will have paradoxical effects and also the implications it has on the physics of time.
The climax that bridges Acts I and II occurs when Markham is flying to America. He attempts to work out the mathematics about the nature of time given what he knows about tachyons. The plane crashes when the pilots get sick, and Markham has a revelation just before he plummets to his death over the Maryland forest. The revelation dies with him, leaving Renfrew, Peterson, and the reader in the dark.
1962-63
Deciding it's time to put up or shut up, Gordon goes over all the data again and asks Professor Claudia Zinnes to run a similar experiment to look for the interference. As Gordon begins obsessing over his work more and more, his relationship with his girlfriend, Penny, suffers.
Finally, things start to come together—Ramsey's experiments prove the importance of the messages and Zinnes confirms the signal. After studying all the data, Gordon finally realizes the truth: The message is coming from the future.
Act III
1998
Peterson gets sick after eating contaminated food. He mostly recovers and he heads home for his bug-out bag. Then he beats feet to his old farmhouse, which he has converted into a Doomsday Prepper's dream, but not before swinging by Renfrew's house to seduce Marjorie.
In his lab, Renfrew continues to transmit his messages until the power runs out, knowing that the death of Markham means he's lost his only hope of understanding the results. Just before the power goes out, he receives a message that might be from the year 2349. Renfrew leaves his lab, deciding to go live the rest of his life with his family.
1962-63
Gordon goes public with his data and findings and is met with acclaim. No longer the joke of La Jolla, Gordon is openly high-fived by his colleagues in the hall.
One day, Gordon watches a news report stating that President Kennedy has been shot, but the report also notes that the president's life was saved by a teenager named Bob Hayes, who stopped Lee Harvey Oswald at the book depository because he was there looking for information on Gordon's research. Gordon realizes something important happened that day even if he can't figure out what.
In 1974, Gordon receives the Enrico Fermi Prize for his research.