The story revolves around Richard Hsieh and his father, who studies dreams. One day, they decide to connect Richard's new Slappy doll to the dream machine as a joke. Suddenly, Richard starts having nightmares with Slappy coming to life and causing chaos. But, they are just dreams, right? However, when his cousin, Willow, visits and she also dreams of Slappy. It's impossible! Yet, when Slappy threatens to invade the dreams of more children, they must find a way to defeat him before he becomes the master of dreams.