Riley Henderson's brother Devin is in California attending a college gaming program while she is stuck alone in Florida with her mom. When a cool nerd named Lucy gives Riley no choice but to get over her shyness and become friends, the best part is both girls are into Dungeons & Dragons. Devin used to be the dungeon master guiding Riley through his intricately planned campaigns. When Lucy suggests that Riley run a campaign for them, she’s willing to give it a shot. Riley discovers not only that she can function without Devin, she figures out the school bus route, how to carry clothes down to the laundry room, and making her own snacks and dinner. But when Devin runs into trouble with his program and returns home, Riley has to help Devin go back to college and prove to her mom that she can take care of herself.