Morikawa first appears in {{CL|1}} in the [[sewer]]s, investigating the body of [[Yuka Kawai]] with most of the rest of the Unit. He also delivers a letter to Kusabi from [[Ryu Munakata]]. Morikawa's biggest role is in {{CL|2}}, in which he irritates Chizuru with his treatment of her, prompting her to attempt to get him transferred. Kotobuki refuses, and Morikawa and Chizuru deal with their strained relationship in the background of the case. It is also implied that they have been having sexual relations. Around the same time Morikawa is tasked with [[Akira|Akira's]] induction into the Heinous Crimes Unit, in which he administers the 100 Question Kumite. In {{CL|3}} Morikawa aids in the Yukimura investigation behind the scenes making brief appearances. Morikawa is next seen in {{CL|4}} discussing recent missing persons cases with [[Morichika Nakategawa|Nakategawa]]. He displays a more lecherous side of his personality while watching popular idol [[Sayaka Bayan|Sayaka Bayan's]] tapped apartment and is taken aback by Chizuru's harshness following Bayan's suicide. He later watches the [[Method Tank]] countdown with the other HCU detectives.  

Morikawa first appears in {{CL|1}} in the [[sewer]]s, investigating the body of [[Yuka Kawai]] with most of the rest of the Unit. He also delivers a letter to Kusabi from [[Ryu Munakata]]. Morikawa's biggest role is in {{CL|2}}, in which he irritates Chizuru with his treatment of her, prompting her to attempt to get him transferred. Kotobuki refuses, and Morikawa and Chizuru deal with their strained relationship in the background of the case. It is also implied that they have been having sexual relations. Around the same time Morikawa is tasked with [[Akira|Akira's]] induction into the Heinous Crimes Unit, in which he administers the 100 Question Kumite. In {{CL|3}} Morikawa aids in the Yukimura investigation behind the scenes making brief appearances. Morikawa is next seen in {{CL|4}} discussing recent missing persons cases with [[Morichika Nakategawa|Nakategawa]]. He displays a more lecherous side of his personality while watching popular idol [[Sayaka Bayan|Sayaka Bayan's]] tapped apartment and is taken aback by Chizuru's harshness following Bayan's suicide. He later watches the [[Method Tank]] countdown with the other HCU detectives.