At school, Tripp Campbell is trying to win a radio contest, which will win him a dinner with his favorite vintage rock band, Iron Weasel. Tripp is asked three trivia questions from the band members. Tripp answers each one correct and wins. At Tripp's house, Tripp and his mother, Beth, meet the three middle-aged rockers, Derek, Burger, and Ash. The guys turn out to be very wild and juvenile for their age.
After dinner, Tripp asks the band if they would like to go to his garage and rock out to one of their songs. In the garage, Tripp manages to impress the guys with his musical skills, while jamming to their song "Pull My Finger" and even asks if he could possibly be their new lead guitarist. The band refuses however, feeling that it would ruin their rock 'n' roll edge to have a kid in their group.
Soon, Tripp's friend, Izzy Fuentes shows up, hoping to meet Iron Weasel and possibly get some souvenirs, but is disappointed to hear that the band had already left. Tripp and Izzy watch the band get into their van, closing the van door, and getting into their pajamas and brushing their teeth. Tripp suddenly realizes that his dream lives in their van. Tripp confronts the band, and the guys admit that they have not been very successful in the music business lately and been living in their band for the last 7 years. Tripp then offers to let them sleep in their guest room, but only if they let they let him play with them at his next gig, so then he can prove to them that he should be their new lead guitarist.
The band agrees, but then laughs at the idea, considering they haven't released an album in years and nobody wants to book them. (While they laugh, Izzy sneaks through the sunroof and snatches a clump of Ash's hair). Tripp says he will do whatever it takes to get Iron Weasel a comeback, even if he has to call the last club in town. However, even when Tripp actually does call the last club in town, he still has to find the band a gig.
A few days later, Beth tells Tripp that last night, Iron Weasel was having a luau in the kitchen, and she doesn't approve having a rock band live in their house. Beth says that even though she supports Tripp's dream and would like to be the "cool mom", she has to be a "good mom" first.
Tripp later finds Izzy searching through their garbage, looking for some half-eaten food from Burger. Their friend, Jared walks in and is stressed about setting up the teacher's appreciation assembly, which he says will be attended by the whole school. Tripp gets an idea to hijack the assembly as Iron Weasel's next big gig.
Tripp then tells Derek, Burger, and Ash (who are all sleeping in three hammocks) that school is going to give them an award for "Band of the Century", and wants them to perform. To celebrate, Derek, Burger, and Ash do the "Weasel Bump", in which they all collapse. (Izzy then steals Burger's half-eaten churro).
At the school, Iron Weasel makes a loud entrance, assuming the whole assembly is for them. The principal gets annoyed by their constant interruptions. Tripp has managed to trick the School Chamber Orchestra into waiting in the janitor's closet, leaving room for him and Iron Weasel to do a rocking performance of "Weasel Rock You". Iron Weasel then does the "Weasel Dive", but the crowd doesn't catch them. (Izzy then sneaks a fingernail clipping from Derek).
Derek, Burger, and Ash are then hurt once they learn that the whole thing was a teacher appreciation assembly and that Tripp had tricked them. But despite this, the guys understand why Tripp lied. They then accept him as the newest member of Iron Weasel.
As they leave the school, Iron Weasel steals the teacher appreciation awards. In the end, Derek, Burger, and Ash finish setting up their bunk beds in the guest room, but the whole thing collapses while they're sleeping in it.
- Logan Miller as Tripp Campbell
- Steve Valentine as Derek Jupiter
- Greg Baker as Burger Pitt
- Stephen Full as Ash Tyler
- Caitlyn Taylor Love as Izzy Fuentes