Nick, age 14, is the main protagonist of the story. He recently lost his mother to the fire that destroyed the family home. He resents moving to an old, dilapidated Victorian mansion in another state, but he soon becomes caught up in the mysteries of the ingenious electric devices stored in the attic. The inventor, Nikola Tesla, has the same first name as Nick, which helps to cement their connection. A bit self-conscious at his new school but smart, intuitive, and courageous, Nick usually manages to wriggle out of the troubles he and his Tesla contraptions get him into. His level-headed, creative intelligence, plus his grasp of the big picture of the Tesla devices versus the Accelerati, make Nick a heroic centerpiece of the tale.

One of the most popular students at Rocky Point Middle School, cheerleader, inventor, and artist Caitlin stumbles upon the Tesla artifacts; using them, she discovers that her superficial social goals pale compared to the deeper, more important challenges she must face. She and Nick partner to solve the mystery of the Tesla devices. Like Nick, she shows intuitive genius and calm resolve; her character models behavior to which readers can aspire.