Nagisa, an Omega who was betrayed by his ex-boyfriend, has lived his life devoted to his beloved son, Haru. Although he had firmly decided that he no longer needed love or a "destined partner," he ends up meeting his "Destined Alpha", Takamine, at the place he moves to. The fluttering in his heart is short-lived, as Nagisa is left infuriated by Takamine's incredibly tactless proposal. However, Takamine has no intention of giving up on Nagisa and, in his own clumsy way, begins to build a relationship with both Nagisa and his son. As they spend their days together—going to summer festivals as a group of three and helping with bicycle training—the romantic feelings Nagisa thought he had long since thrown away begin to bud once more...