Kyle is a 13-year-old finishing sixth grade in Kansas. He dislikes confrontation, avoids physical conflict, and prefers to be prepared and in charge of his surroundings. Though he struggles with self-doubt and feels cowardly about avoiding his bully, he possesses a strong moral compass and steps up as a leader when natural disasters strike during his family's Oregon vacation.

BeeBee is Kyle's eight-year-old sister who accompanies the family to the Oregon coast. She is highly intelligent, especially regarding money and finance, and even names her stuffed bear Bill Gates. Despite her sharp wit and financial know-how, she relies entirely on Kyle for guidance and protection when they are separated from their parents during an emergency.

Daren is a large, physically imposing boy who has mercilessly bullied Kyle since kindergarten. He is self-centered, ungrateful, and deeply concerned with maintaining a tough reputation. When his mother wins the same real estate award as Kyle's father, Daren unexpectedly joins the Oregon trip, creating an immediate conflict for Kyle.

Kyle and BeeBee's parents work in real estate and are characterized by their levelheadedness and open communication. They trust Kyle's maturity, allowing him to babysit BeeBee while they attend an adults-only awards cruise on a yacht. This trust inadvertently separates the family when the earthquake occurs.

Norm and Josie are a kind elderly couple living near the Oregon coast. Unlike many locals who ignore the town's warning sirens due to false alarms, they take the threat seriously and evacuate. They offer guidance, a flashlight, and emotional support to Kyle and BeeBee as they flee the coast.

Pansy is Norm and Josie's pet dog who accompanies them during the evacuation. She possesses a keen natural instinct for danger, physically reacting before the waves strike to provide vital early warnings to the humans around her.