Lee Junho is nobody. A restaurant worker who cleans up after people who never see him. That changes the night he swallows something that shouldn't exist — a fragment of something not from this world. Now he can smell what people feel. Their fear. Their lies. Their secrets. And something else — a scent unlike anything human, coming from behind the door of apartment 4C. He doesn't know what it means yet. But he's going to find out. Across the country, others are changing too. A surgeon whose mind runs faster than he can control. A forensic toxicologist who can smell a lie before it leaves someone's mouth. A journalist who hears the truth in every heartbeat. None of them know the others exist. None of them know they're being hunted. Something fell from the sky. It scattered. And it's already inside them.