Lily and her brother Rory have just moved into a new house after their family spent months renovating it. The formerly rundown, creepy old house is now totally transformed into a tech lover's dream. Rory has installed a smart device called Mastermind that can turn on lights, lock doors, and even open the windows, among other things. He and Lily love showing off what the Mastermind can do. But someone doesn't love the changes--the ghost of the girl who died in the house. She's angry--and ready for revenge.