The Nameless Hero by Lee Bacon
Joshua Dread is just your average sixth grade boy who is excited about summer break. Well, maybe he's not that average. You see Joshua has supervillain parents and a friend whose father is a superhero. Plus Joshua has special powers. He and his friends receive an invitation to attend a mysterious summer camp for children who are "Gyfted and Talented." The summer camp turns Joshua and his friends into a superhero team. The team ends up fighting the villain Multiplier who Joshua finds out is working for the evil maniac Phineas Vex, who tried to kill him and his parents last summer (Book 1 - Joshua Dread). Will Joshua survive? Will the new superhero team be able to stop Vex? You'll have to read to find out.