Skylar (Olivia Holt), a fearless teenager with a powerful singing voice, prepares for the ultimate Halloween bash with her best friends. However, the plan for Skylar to sing at the party – with rock band cutie Ryan Dean (Luke Benward) – is crushed when her parents make her stay home. When she attempts to sneak out of the house, she accidentally unleashes a monster who is determined to change the fate of Skylar and her family forever. As Skylar's world is turned upside down, she learns that her parents have been keeping a big secret – that she comes from a long line of monster hunters. Now, it's up to Skylar and her friends to channel their inner strength and conquer more than just this monster.