"Hell Girl: Three Vessels" is the third season of the "Hell Girl" series, continuing the dark and supernatural themes of its predecessors. The narrative revolves around Ai Enma, a mysterious girl who operates a supernatural website accessible only at midnight. Those who harbor intense hatred and a desire for revenge can summon her by entering the name of their tormentor. Ai offers to send the targeted individual to Hell, but at a cost: the summoner must also forfeit their soul to Hell upon death.

The season introduces new characters and expands on the lore of the Hell Correspondence website. Ai is accompanied by her three companions: Hone Onna, a seductive woman with a skeletal appearance; Ichimoku Ren, a stoic ferryman; and Wanyuudou, a man with a wheel for a head. Together, they facilitate the process of delivering vengeance while maintaining the balance between the living world and Hell.

The episodic structure of the series explores various individuals who seek retribution against those who have wronged them. Each episode delves into the personal grievances of the summoners, often highlighting themes of betrayal, abuse, and societal injustice. The stories are interconnected by the overarching presence of Ai and her companions, who observe the consequences of human actions and the cyclical nature of hatred and revenge.

A significant addition to this season is the introduction of Kikuri, a mysterious doll-like entity who serves as a guide for Ai. Kikuri's role and origins remain enigmatic, adding an element of intrigue to the narrative. The season also delves deeper into Ai's backstory, revealing more about her tragic past and the circumstances that led to her becoming the Hell Girl.

The tone of "Hell Girl: Three Vessels" remains consistent with the previous seasons, blending horror, drama, and moral ambiguity. The series does not shy away from depicting the darker aspects of human nature, often leaving viewers to ponder the ethical implications of seeking vengeance. The episodic format allows for a diverse range of stories, each contributing to the overarching exploration of the consequences of hatred and the price of revenge.