Hoops & Yoyo can't wait for Halloween... but they have waited until the last minute to begin their search for costumes. When that search leads them to the mall, they are accidentally locked inside after closing. They discover that this favorite daytime haunt is actually haunted at night. But through a series of frightening events, they learn that "monsters" aren't always who they seem to be.
Jill Parrish is trying to rebuild her life after surviving a terrifying kidnapping attempt. Though she is having a difficult time, she takes small steps toward normalcy by starting a new job and inviting her sister, Molly, to move in with her.
When an evil spirit known as Pitch lays down the gauntlet to take over the world, the immortal Guardians must join forces for the first time to protect the hopes, beliefs and imagination of children all over the world.