The Night Beyond the Tricornered Window - S01

Kousuke Mikado has been able to see spirits for as long as he can remember. He is terrified of them, so he tries to hold his ability back by wearing glasses. One day, while working at a bookstore, he draws the attention of Rihito Hiyakawa, an eccentric medium who is sure that the two of them were destined to meet. Because of Hiyakawa's antics, Mikado is pulled into the world of the paranormal, and Hiyakawa promises that he will shed his fears if Mikado stays with him. As they keep working together, the two uncover a series of malicious curses that all point to the same name: "Erika Hiura." What is this person after, and how are they connected to Mikado and Hiyakawa?