Lee Jain has lived on Earth for 3.5 billion years, dying and being reborn as countless animal species. Now in his final life, he is reborn in South Korea as a human, the species he hates most. Having inherited all the animal superpowers from his past lives, Jain is determined to survive and wipe out humanity. But when a sudden car accident erases his memory, Jain crosses paths with new beings that force the question: is humanity worth saving, or is it bound for extinction?