Season 1 Plot Twists & Finale: So Mun discovers that the car accident seven years ago that crippled him was not a random mishap, but a calculated assassination carried out by corporate hitmen working for Taesin Group and Mayor Shin Myeong-hwi. The primary antagonist, Ji Cheong-sin, evolves into a Level 4 spirit by absorbing multiple human and spirit souls. When backed into a corner, Ji Cheong-sin commits suicide to prevent exorcism, allowing the Level 4 spirit to transfer directly into Mayor Shin Myeong-hwi. In the finale, So Mun masters the ability to summon the Yung territory anywhere, successfully exorcising Mayor Shin. In Yung, So Mun meets his parents' souls, who initially do not recognize their grown son until he tearfully reveals his identity, granting them a peaceful ascension.
Season 2 Plot Twists & Finale: Three Korean evil spirits (Pil-gwang, Gelly, Wong) hide in China, murder local Counters, and absorb their abilities (granting Pil-gwang extreme telekinesis and Gelly psychometric memory erasing). Firefighter Ma Ju-seok—a close friend of So Mun—loses his pregnant wife Min-ji to a murder committed by the spirits. Driven insane by grief, Ju-seok allows an evil spirit to possess him.
The ultimate twist occurs when Pil-gwang allows Ju-seok to murder him, deliberately enabling Ju-seok to absorb his soul. However, Pil-gwang's consciousness takes over Ju-seok's body from the inside, creating the "Complete Evil Spirit". Yung orders the immediate execution of Ju-seok's body, but So Mun refuses to kill his friend. Instead, So Mun projects his spirit into Ju-seok's mental domain, locating Ju-seok's inner weeping soul and convincing him to fight back. Ju-seok regains control long enough for So Mun to safely summon Pil-gwang to hell while preserving Ju-seok's human life.