A massive sinkhole opens up in the middle of Los Angeles, separating a family between two worlds. The mother and son fall into an unexplainable primeval land alongside a group of strangers trying to figure out where they are, and how to get back home. Left above is a daughter, who barely manages to survive the disaster, and the father, whose troubled past and hallucinations make him an unlikely choice to help solve the mystery -- and reunite the family. But when he realizes…