Monster High takes part in an annual "roller maze" tournament, a roller sport where two competing teams must make their way through a labyrinth full of dangerous obstacles. Each team faces aggressive tactics by rival players, intended to temporarily incapacitate some players. Early in the tournament, the gargoyles of Granite City High win their game by injuring most of the players of the Monster High team. The leading player Clawd Wolf suffers leg injuries in an accident, which is later revealed to be an act of deliberate sabotage. Monster High is forced to surrender the school crest to the gargoyles. The school building starts to fall apart without the crest, and the morale of the students and teachers is low. With only two players remaining in good health, Frankie Stein decides to find replacement players. Lagoona Blue outperforms all of the male candidates, but every boy refuses to serve with a girl on the team. Following their resignations,Lagoona and her friends form an all-girl team for the tournament. Operetta rescues two of the new players from a serious accident, and displays her superior skills in the sport. When invited to join the team herself, Operetta turns the offer down. She is a lifelong loner and rebel, and she has never joined any team. While she changes her mind when convinced than the team defies any tradition, Operetta still has some problems in working well with others. Clawd and the revived android girl Robecca Steam serve as the team's coaches, and the female gargoyle Rochelle Goyle voluntarily defects to their team. But Monster High's victory in the tournament is only secured by using the gargoyles' cheating tactics against them. The gargoyles are using Toralei Stripe as their spy within Monster High, and Operetta is passing deliberately false information to the spy and to the rival team.