| Adrian |
Clement | Grace's seatmate. |
| Kyle |
Clement | Adrian's brother. |
| Jade |
Coleman | Maddy's roommate. |
| Clyde |
Gable | Adrian's roommate. |
| Shelley |
Graber | Grace's schoolmate. |
| Alyssa |
Griffin | Grace's friend. |
| Trent |
Gutter | Man who found Grace; chaperone on the trip. |
| Nicole |
Harris | Grace's friend who was on the trip with the sisters. |
| Krista |
Hawthorne | Ryan's girlfriend. |
| Ryan |
Jacob | Member of the trip; Maddy's classmate. |
| Caleb |
Jones | Nicole's boyfriend. |
| Mateo |
Ramirez-Hernandez | Star of the basketball team. |
| Marc |
Reyes-Castillo | Nicole's lawyer. |
| Katie |
Sanderson | Forest Lane Academy staff member. |
| Grace |
Stoll | Narrator and protagonist. |
| Madelyn |
Stoll | Grace's sister; missing. Aka: Maddy. |
| Tori |
Syblonski | Grace's roommate. |
| Dorene |
Williams | Scholarship program owner. |
| Avery |
| School principal. Aka: Principal Avery. |
| Brayden |
| Adrian's mother's deceased baby. |
| Bryson |
| Ryan's friend. |
| Cramer |
| Grace's therapist. Aka: Dr. Cramer. |
| Erica |
| Maddy's only friend. |
| Finch |
| Stoll family's elderly neighbor. Aka: Mrs. Finch. |
| Fizzy |
| Maddy's dog. |
| Haines |
| English teacher. Aka: Mrs. Haines. |
| Holstof |
| Staff member originally signed up for senior sabbatical. Aka: Mr. Holstof. |
| Holstof |
| New hot computer teacher. Aka: Mr. Holstof. |
| Howard |
| Lead detective on the case. Aka: Detective Howard. |
| Jade |
| One of Grace's friends. |
| Jones |
| Detective Howard's officer. Aka: Mr. Jones. |
| Mackayla |
| One of Grace's friends. |
| Miller |
| School administrator. Aka: Mrs. Miller. |
| Patty |
| Grace and Maddy's grandmother. |
| Richardson |
| The school counselor. Aka: Mrs. Richardson. |
| Sanchez |
| School nurse. Aka: Mrs. Sanchez. |
| Sanderson |
| Staff member originally signed up for senior sabbatical. Aka: Mrs. Sanderson. |
| Stoud |
| Adrian's teacher. Aka: Ms. Stoud. |
| Thelsman |
| Grace's doctor. Aka: Dr. Thelsman. |
| Triker |
| History teacher. Aka: Mr. Triker. |
| Zoey |
| Erica's roommate. |
