Plot

Two friends try to form a heavy metal band with a cellist for a Battle of the Bands.

The only two kids who care about heavy metal in their high school want to form a heavy metal band but fail to find a bass player. They do, however, find a girl adept at cello. If these three can settle their differences, work together, and stay out of trouble, they could win the upcoming Battle of the Bands.

Metalhead Hunter Sylvester (Adrian Greensmith) jams with his best friend, the insecure Kevin Schlieb (Jaeden Martell), who does not know quite well how to play a whole drum set because he only plays a single drum on the school's marching band. During one of the marching band practices, Kevin witnesses mentally ill Scottish student Emily (Isis Hainsworth) having a full meltdown and quitting the band because of her lack of skills with the clarinet. Hunter and Kevin are struggling for funds to buy a full drums kit, as it costs a $1000. Later that day, Kevin drags Hunter to a party at Clay Moss' (Noah Urrea) house and tries to be a normal kid while Hunter feels misplaced. Clay has his own band called the Mollycoddle. Kevin gets drunk and flirts with a girl named Kendall (Analesa Fisher), while Hunter gets into an altercation with jock Rocky "Skip" Hoffman (Phelan Davis). Skip is the school bully who picks on nerds and has a thing for Hunter and Kevin.

In the aftermath, Hunter discovers that the school will hold a "Battle of the Bands" and it prompts him to sign up his and Kevin's band named Skullfucker. Hunter has ambition to achieve fame and fortune via heavy metal, and so this competition is huge for him. Hunter is obsessed with winning. Hunter steals his father's AMEX card and spends US$ 13,500 in gear, including a full drum kit for Kevin. Kevin starts practicing at school and during one of those sessions, he discovers that Emily is in fact a skilled cello player. They become interested in each other, which prompts Kevin to give her a copy of playlist of metal songs that Hunter assigned him as a "homework". Meanwhile, Hunter tries to find a bassist to complete the trio, only to be unsuccessful because of lack of interest from the other students (and the fact that Hunter keeps insulting them), and has a series of run-ins with Skip (skip cuts Hunter's hair and destroys his car).

Kevin unsuccessfully tries to pitch Emily as their new bassist to Hunter. HUnter is rude to Emily and says that she doesn't fit with his band's image. Afterwards, Kevin calls Emily to apologize for Hunter's behavior and they end up having sex in the back of Emily's van. Kevin and Emily become a couple, which enrages Hunter, who believes that she will be their "Yoko Ono". Clay hears Kevin playing drums and, since Clay's drummer is going to rehab for substance abuse, Clay asks Kevin to join his band Mollycoddle, for his sister's wedding that weekend. During a speech class, Hunter teases Emily (about how she will never understand what "metal" is, and that she is keeping Kevin down) to the point of her melting down, attacking him, and breaking his guitar in the process. Those two facts lead to an argument between Hunter and Kevin, who leaves Skullfucker.

Kevin performs with Mollycoddle at Clay's sister's wedding, while Hunter tries to break into the wedding to get Kevin back into Skullfucker and is arrested for trespassing. Afterwards, Kevin is invited to hang out with Clay's friends and to perform with Mollycoddle on the Battle of Bands, which he reluctantly accepts. Kendall invites a drunk Kevin into the pool and flirts with him. While they make out, Kevin's conscience materializes in the form of heavy-metal musicians Scott Ian, Tom Morello, Kirk Hammett and Rob Halford. Halford makes Kevin realize that he indeed loves Emily and gets back with her. Kevin also realizes that he needs Hunter back, only to discover that Hunter was sent to rehab by his father (Brett Gelman), as a punishment for his misbehavior.

Hunter discovers that the clinic is run by Dr. Troy Nix (Joe Manganiello), famed lead guitarist of metal band Killoton and former Battle of the Bands champion; Nix explains that Killoton broke up because of his alcohol abuse and fraught relationships among the band members, which prompted Nix to get his life straight, become a doctor and help other addicts. Dr. Nix says that, while Hunter is fit for discharge, it won't happen until the next week because of the clinic's policies. Kevin breaks into the clinic and breaks out Hunter and Mollycoddle's drummer; they run into Dr. Nix during their escape, but Nix lets them go after giving Hunter a better guitar pick. Hunter and Kevin go to Emily's home, where Hunter apologizes to Emily and invites her to be their cellist, but Emily turns them down, saying that she's not ready yet.

On the night of the Battle of Bands, Kevin apologizes to Clay, saying that he can only play in one band, but presents Mollycoddle's drummer, now sober, to replace him. As Kevin and Hunter are getting ready for their performance as a duo Emily appears to perform with them with an electric cello and decked out in gothic-metal attire. Just as they're about to take the stage, Dean Swanson (Sufe Bradshaw) warns them that the name "Skullfucker" is inappropriate for the event, forcing Emily to quickly change the band's name to Skullflower. Despite initial skepticism and confusion, their performance wins over the crowd, until a drunk Skip is shoved out of a mosh pit and pushes Hunter into his amp stack in the middle of his solo, making Hunter fall down and get crushed by his amplifiers, breaking his leg in the process.

Later, Kevin, Emily and a recuperating Hunter read the city's newspaper telling that they went viral with their concert, despite losing the Battle of Bands and coming in second place to Mollycoddle; they conclude they're the moral winners of the contest (they were the last band to play, which made them headliners, the entire crowd loved them and sang the chorus of their original song, and Hunter's injury landed them on the front page of the newspaper) and they begin to practice in Hunter's basement with renewed vigor and camaraderie.