Kyle is an easy-going twelve-year-old seventh grader who loves video and board games, especially those created by his hero, Mr. Lemoncello. He frequently feels overshadowed by his athletic and academic older brothers but finds that games provide a fair, fun environment. Friendly and optimistic, he takes a sudden interest in a library essay contest when he discovers it features an overnight lock-in with access to new games.

Mr. Lemoncello is an eccentric billionaire and world-famous game maker who grew up in Alexandriaville. He attributes his success to the quiet refuge of the town's original public library, which offered him a calm environment away from his nine siblings. To share his love of learning and games, he funds the construction of a highly advanced new library and designs an elaborate overnight experience for local students.

Charles is a wealthy twelve-year-old seventh grader who constantly wears a suit jacket, khakis, and a tie. He lives by his family's highly competitive philosophy that they never lose at anything. Arrogant and manipulative, he views the library overnight event strictly as an obstacle course to conquer rather than an experience to enjoy.

Dr. Zinchenko is a tall, red-haired, world-famous librarian hired by Mr. Lemoncello to oversee the grand opening of the Alexandriaville library. She is highly organized and manages the library's high-tech features and staff through an earpiece headset. She strictly enforces the rules and expects the students to treat the facilities with respect.

Sierra is a seventh grader who spends most of her time reading following her parents' divorce. She is a quiet, observant bookworm who frequently prefers stories to socializing with her peers. Her extensive knowledge of books and authors makes her a valuable asset during library-based challenges.

Haley is a popular, appearance-focused seventh grader who initially looks down on students excited about the new library. Beneath her haughty exterior, she is highly motivated to win the library competition in hopes of securing a spokesperson role to help her family financially.

Akimi is Kyle's best friend and a fellow game enthusiast. She is highly organized and practical, often keeping notes and tracking information for the group. She easily bonds with Kyle over strategies and relies on his gaming expertise while providing her own systematic approach to problem-solving.

Miguel is an enthusiastic seventh grader who serves as a library aide at school. He recognizes Dr. Zinchenko immediately at a school assembly, showing his deep knowledge and appreciation for library science. He frequently shares high-fives and inside jokes with Kyle.

Andrew works alongside Miguel in the school library but harbors a chip on his shoulder regarding recognition and rewards. He views the library competition very seriously and is easily intimidated by more aggressive personalities, making him susceptible to manipulation.

Mike is Kyle's seventeen-year-old older brother. He is a talented athlete who frequently wins physical competitions, creating a friendly but noticeable sibling rivalry that drives Kyle to seek victories in board games.

Curtis is the middle Keeley brother, known for his strong academic performance. His intelligence sometimes makes Kyle feel inadequate in school subjects, though Curtis remains supportive of his younger brother's gaming interests.

Mrs. Tobin was the director of the Alexandriaville public library in the 1960s. She mentored a young Mr. Lemoncello, providing him a quiet space to read and helping him develop his very first game. She now appears as a highly advanced hologram to assist the new library patrons.

Clarence is a serious security guard employed at Mr. Lemoncello's new library. He wears sunglasses and a black blazer, standing by the massive bank vault doors to ensure the children follow Dr. Zinchenko's strict guidelines.

Mrs. Cameron is Kyle's seventh-grade homeroom teacher. She enforces deadlines strictly, refusing to accept Kyle's much-improved second essay after the contest deadline has officially passed.

Yasmeen is a twelve-year-old student from Alexandriaville who wins the essay contest. She is quick to act during the library game and confidently attempts to use a fire exit to secure an early win.

Rose is a responsible twelve-year-old who wins the essay contest but chooses not to participate in the extended escape game due to a prior commitment to her soccer team.

James, known as "Uncle Jimmy," is the Head Librarian at the Library of Congress. He represents the Chiltington family's extensive connections and resources, which Charles intends to use to his advantage during the competition.