Sam is a 12-year-old boy attending summer camp in Maine while his mother completes a rehabilitation program. He possesses an excellent internal compass and a wealth of outdoorsy knowledge taught by his late father. Thrust into a life-or-death situation, he uses his practical skills to travel through the burning forest. He carries a heavy sense of responsibility for his family.

Delphy is a 14-year-old girl who becomes stranded in the Maine woods after missing the evacuation at her fitness camp, Camp Calusa. Tall and physically capable, she provides a counterbalance to Sam's cautious nature with her direct action. She comes from a large, close-knit family that owns a Greek restaurant, giving her a supportive background that she fights to return to.

Also known as Charles and James Binney, these two men are arsonists deliberately setting fires in the Maine woods. They target camps and vacation homes out of anger toward outsiders buying property in the state. Armed with dirt bikes and a hostile ideology, they create a secondary, highly volatile threat alongside the natural disaster.

Sam's mother and late father heavily influence his choices during the crisis. His father, a former trucker who died in a fiery crash in Afghanistan, is the source of the practical survival skills Sam relies on in the woods. His mother is currently in a substance abuse rehabilitation program for a prescription drug addiction. Sam focuses on surviving so he can return home and support her recovery.

Phat Freddy Bell is a local radio host for WRPZ, 98.6 FM, broadcasting from a small station in rural Maine. He provides constant updates about the fire's movement, serving as the only link to the outside world for those stranded in the woods. He is dedicated to his job and continues his broadcast even as conditions worsen around his station.

Aldrich Brown is a Korean War veteran and the original owner of the old Jeep Sam finds in a logging camp shed. His vehicle becomes a crucial survival tool for the stranded children as they attempt to outrun the flames.

Delphy's younger twin sisters live with their parents and extended family. They represent the large, stable home life Delphy is fighting to return to, highlighting the differences between her upbringing and Sam's isolated home life.