Under Diamond Bar - Tammy Hilt Rivera

An invisible portal opens. .and suddenly the River kids of Diamond Bar discover they've been living side-by-side with a parallel world of hidden beings-beings who are no longer content to live and let live. But are they friends or foes? When Crystal, the youngest River, disappears one Halloween day, her brother and sister can no longer ignore their invisible neighbors. Joshua and Silver River enter a race to save their family from unthinkable doom at the hands of an ancient, evil ruler known as Svang...