The Mikadono sisters—Miwa, Niko, and Kazuki—stand at the pinnacle of Saika Academy as its Three Royals, renowned respectively as prodigies in shogi, karate, and theater. Unfortunately, they have drifted apart from each other due to their overwhelming dedication to their fields, effectively turning them into strangers living under the same roof. Enter Yuu Ayase, the son of the late Subaru Ayase, a legendary actress who graduated from Saika. Unlike his mother, Yuu lacks any extraordinary talent whatsoever, much to the disappointment of those who knew her. Still, he transfers to her alma mater with one quiet promise in his heart: to fulfill her final wish that he build a true and happy family. It just so happens that the Mikadono patriarch is also Subaru's longtime friend and benefactor, and he offers Yuu both a place to stay and a fresh start. Thrust into the lives of three estranged sisters who act cold toward him, Yuu may not be a genius himself, but the clumsy sincerity he brings might be what they all need to start anew.

After the success of his crowdfunded movie featuring the woman of his dreams, Chizuru Ichinose, university student Kazuya Kinoshita resumes his life of lies and deception. Although he pretends that he has been in an ideal relationship with Chizuru for more than a year, Kazuya still mostly sees her through a rental girlfriend company's services. However, after Kazuya attends a private party with Chizuru, he reaches the decision to finally confess his feelings to her. Unfortunately for him, his trial girlfriend Ruka Sarashina and his ex-girlfriend Mami Nanami continue to complicate his already messy attempts at romance. While he is forced to keep up his facade, Kazuya is under pressure to find a solution to his ever chaotic love life.

A lot has happened for Nagi Umino and Erika Amano: they were swapped at birth, learned of their engagement, and have started living under the same roof. The two now share their home with Nagi's sister, Sachi, and his crush, Hiro Segawa. Despite this unusual domestic situation and frequent quarreling, the group is beginning to settle into a life together. However, the return of Nagi's childhood friend Ai Mochizuki to Japan complicates things. Ai suddenly declares her intention to marry Nagi, and although he turns her down, she is committed to having him all to herself. Now with four girls around, each with their own thoughts about him, Nagi must figure out his own feelings and the best way forward.

Fifteenth season of Yami Shibai.