Kwazii and the gang celebrate music with concerts, singing, dancing, and band playing, but Mal's grouchy mom, Maleficent, doesn't like music and decides to steal the instruments, break the CDs, and mess up the dance floors.
The episode begins at the Disney Junior Town Plaza where the residents are preparing decorations, food, and even music for the Magical Melodies Weekend Festival coming this Saturday. Meanwhile, in the Octopod, the Octonaut Stars were practicing their new song, Music is Everywhere, while the crew and the Vegimals were happily listening to it.
After finishing their song, Kwazii jumps up with excitement and compliments to his bandmates that they are doing a great job because one they get a hang of it, they'll be ready to rock out at the festival coming soon. When they practiced one more time, Captain Barnacles, Peso, and even Kwazii were exhausted that they had to sleep in the game pod to refuel their energy. But later that night, a shadowy figure begins to sabotage the preparations for the festival. Then after it was done, it let out an evil cackle and left.
The next morning, Kwazii, Barnacles, and Peso were eating breakfast and got back up to the game pod to practice their song again. When suddenly, Kwazii's iDisney phone began to ring and he signals his friends to stop as he presses the call button and Mayor Mickey Mouse tells him that someone has ruined the decorations for the festival, so they'll have to cancel it unless they find out who has done the mess. Kwazii freaks out as he drops his electric guitar and teleports to the plaza to personally talk to Mickey. He begs to him that he and his friends will find the troublemaker and catch him or her or it, then save the festival before Saturday.
As Mickey gives in, he tells Kwazii that they'll keep the festival going only if he and his friends find clues from last night. Kwazii teleports back to the game pod and explains to Captain Barnacles and Peso that they can't play at the festival unless they stop whoever's sabotaging the place. Later at the plaza, Kwazii, Captain Barnacles, Peso, and even Sofia, Captain Jake, and Sheriff Callie were looking for some clues just when the four Descendants showed up to see what was going on.
Just then, Sofia finds a piece of black cloth that ripped off from the culprit's dress. Mal goes over to take a closer look and soon realizes where it came from. It was a piece of her mom, Maleficent's, dress. So that confirms it, Mal's mom was behind all of this, but why? The Disney Junior Club, along with the Descendants, then decide to stay in the plaza overnight to find.
As night fell, Kwazii helped get everything fixed with his bracelet's magic and settled in for the night with his friends. But Kwazii stays behind to keep a lookout for Maleficent if she tries to sabotage anything again. Unfortunatel, it wasn't easy and Kwazii fell fast asleep, until... something woke him up! As he peeked from his hiding spot, Kwazii spots Maleficent trying to break the musical instruments! Kwazii knew that he had to do something, and fast!