A magnificent epic adventure begins here - when a huge sink suddenly cracks in downtown Los Angeles, hundreds of people and countless buildings are instantly swallowed into the bottomless abyss.Those who fell into it were horrified to find themselves in a mysterious and dangerous primitive world. Faced with unfamiliar environments and unknown threats, they can only survive in this barren land by relying on each other and working together. And above the surface, the whole world is trying hard to find the truth behind this disaster.At the same time, a family separated from their flesh and blood due to this catastrophe embarked on a path of exploration full of difficulties and unknowns.They not only want to uncover the secrets behind this strange phenomenon that is beyond common sense, but also seek hope in despair and reunite in chaos.This is not only an exploration of science and nature, but also a affectionate journey about love, courage and belief.