Plot

You Keika is heir of Exorcists, stricken with poverty and computer tech, until one night he gets hit by car and become a ghost. Tanmoku Ki appears and asks him to make a pact to fight Evil Spirits. Here starts the friendship of our heroes.

You Keika, the heir of an old famous family of Exorcists, is stricken with poverty after losing his parents and struggles as a street fortune teller and a part time computer tech. One night at a junkyard, he meets a mysterious and charismatic Exorcist, Tanmoku Ki, who is fighting an evil spirit. To compound his misfortunes, he gets hit by car and becomes a ghost. Tanmoku Ki appears and asks You Keika to make a "pact" with him to fight Evil Spirits together. Here starts the friendship of our heroes.—Crunchyroll

Low on luck after a series of unfortunate events, You Keika works part-time to try bringing himself out of a life of poverty. After a strange encounter with a white-haired man in a junkyard, You wakes up to discover that he was killed in a sudden accident and has become a spirit. The man he had encountered, Tanmoku Ki, is revealed as the 13th Youmeshi of the Tanmoki, the highest-ranking exorcist family of China. Noticing the wandering spirit, he offers You the opportunity to form a pact: he will offer You protection from humans and in return, You will have to become his spirit shadow, keeping him safe and guarded at all times. From then on, the two face untold challenges in the spiritual world, striving to keep those around them safe from harmful spirits. Along the way, the pact they formed grows into something more; a bond that neither of the two ever expected. Behind their roles as master and servant, a lingering admiration begins to emerge.—MAL Rewrite

Season 2: Tanmoku Ki is an exorcist with the responsibility of cleansing the spirits of the world and in doing so he serves as a priest protecting the balance between heaven and earth at the cost of his own life span. However, he is destined to fight not only the evil spirits who constantly aim for his life and spiritual powers, but also those who covet his position and influence. Their attacks never cease and Tanmoku Ki must always keep fighting.In the midst of all this, the only person that Tanmoku Ki is able to face as completely as himself is You Keika, who is Tanmoku Ki's spirit shadow. Are they truly just "exorcist" and "spirit shadow"? What turn of fate has brought them together?The curtain rises on a new story and Tanmoku Ki's past that was not able to be told in the first season of the anime. Just who is this person called "Shouken" who lies dormant in Tanmoku Ki's memories?—Crunchyroll