Fourth season of Yong Sheng.

Not long after forming their partnership, detectives Ron Kamonohashi and Totomaru Isshiki have proven adept at solving various cases together. However, the two are further motivated to continue their work when they discover that the House of M—an infamous crime syndicate—orchestrated Ron's expulsion from the prestigious Detective Training Academy BLUE five years prior. It appears that this group is also linked to Ron's mysterious ability that causes those around him to lose their lives, a phenomenon which Ron is desperate to stop. A member of the House of M soon starts to commit boastful serial murders around Shibuya as an act of provocation toward Ron. Consequently, the investigative pair must do their best to apprehend the culprit for the sake of justice as well as learning more about Ron's dark past and present condition.

Himari Kino is a cheerful and outgoing girl who is able to make friends with anyone she wants. When she enrolls in high school and attends the freshman opening ceremony, Himari falls in love with Yori Asanagi, a reserved upperclassman, during Yori's band performance. After the show, Himari blurts out her love, but Yori is inexperienced when it comes to romance. Yori, who did not expect this outcome at all, looks for answers from her friends and music. She decides to respond to Himari's confession, and to her surprise, Yori discovers that Himari fell in love with her music and performance rather than Yori as a person. Despite the shock, Yori desires to make Himari truly fall in love with her. The duo spend time together after school on the rooftop, where Yori usually plays her guitar with hopes to change Himari's feelings for her.

Jill Savelle—fiancée of the crown prince Gerald der Kratos and known as the Lady Goddess of War—is being hunted down by the same country she swore to protect. Betrayed by her betrothed, she is framed as a traitor and imprisoned. In her last moments, Jill is filled with regret, but just as death approaches, she awakens six years in the past. This time, she will not be a mere pawn. Now as a 10-year-old girl, Jill resolves to escape her imminent engagement to the prince. To this end, she jokingly professes her love to the 19-year-old dragon emperor Hadis Teos Rave, who will one day stain the land in blood due to madness. But against all expectations, he accepts! In contrast to the tyrant from Jill's memories, the Hadis of this time is a kind albeit unfortunate emperor. Can Jill prevent Hadis from descending down the same dark, villainous road, or is he bound to an inevitable future?