In honor of their deceased father's dream, siblings Kiku Takane and Ryuuji Takane set their sights on becoming champions in the boxing world. As Kiku takes on the role of trainer, Ryuuji focuses on honing his skills as a boxer and mastering the legendary Boomerang Hook technique. Through intense bouts with various opponents, Ryuuji undergoes significant personal growth and development. Now, as the junior high boxing tournament kicks off, Ryuuji prepares to face off against his long-standing rival, Jun Kenzaki, in a pivotal showdown that will test his mettle like never before.