The summer of 2024, when Solar Cycle 25 reaches its highest level of solar wind activity, is a time of auroras and adventure for Marty Clark, high school graduate, and her former tutor, Cy Riverton, age 18, a physics and math prodigy entering the master's program at the university.
For Cy, the hike to Dead Man's Drop Cliff means gathering information to solve the toughest physics problem he has ever faced: How did his friend, Eddie Burrows, disappear from there during 2024 Spring Break and end up in Pennsylvania in the year 1857?
Marty joins the hike to spend time with Cy, someone she hopes will someday be more than a friend, just days before she is to leave on a two-month history immersion tour. She has no idea just how immersed in history she will shortly become.
As a joke, Marty calls Cy's cell number while on Dead Man’s Drop Cliff. That starts an adventure through time that takes her from 1748 western Pennsylvania to 1758 Maryland where the fox terrier, Hunter, joins her. She befriends a Lenni Lenape woman, Green Corn, and stays with an English colonial woman, Maggie. She must rely on her wits as she is threatened by tribal warriors and British colonists alike.
Only after Marty disappears does Cy realize how much she means to him. Unlike Eddie, Marty’s cell has rechargeable solar batteries, which he believes is key to getting her back. He communicates with Marty using text messages as they work to solve the physics involved with her travel back through time.
Because law enforcement is already suspicious of him due to his involvement with Eddie, Cy decides his best hope for helping Marty is for him to keep her disappearance a secret. Their efforts become more urgent as FBI Special Agent Lee Hardin, refuses to “cold case” Eddie's disappearance and pursues Cy relentlessly.
Cy and Marty race against time and across eras in an effort to use the power of auroras to become reunited before it is too late for both of them.