The journey to find all eight sacred gems continues, as Sousuke and Shino travel in search of the remaining gem holders. From the shadows the Imperial Church continues to scheme, and a mysterious woman seeks to fulfill a sinister plot with the gem holders at its heart. As the origin of the gems comes to light, so does the truth behind Sousuke's doppelganger, Ao, as he resurfaces with his own goal—one involving Sousuke and his gem! (Source: Sentai Filmworks)

Although the city of Fukuoka might look relatively peaceful at first glance, in actuality it houses a thriving mixture of dangerous individuals such as killers, detectives, and professional revenge seekers right beneath its surface. Among their number is Zenji Banba, a laidback and observant detective who is investigating the work of other hitmen companies in the area. However, Banba might not be the only one with a bone to pick with these organizations, as Xianming Lin, a crossdressing male hitman in the employ of one such company begins getting fed up with his lack of jobs and pay. One day, after Lin's current target commits suicide before the hitman could reach him, his company refuses to pay him even half the amount they were originally supposed to for the assassination. Frustrated, Lin requests another mission and is offered the job of taking out Banba, whom his organization believes has been interfering with their business. However, when Banba arrives at his home and finds the hitman inside, Lin surprisingly doesn't even attempt to kill him. Instead, he offers the detective another option: to join him and form a team. With the offer on the table, exactly how will Banba respond, and just what plans does Lin have in store for the underground world of Fukuoka?

Tatsuya Kimura is beginning to feel left behind. With his friends Ippo Makunouchi and Mamoru Takamura holding the championship belt in their respective weight classes, Kimura's inability to become Japan's Junior Lightweight boxing champion eats away at him. Scheduled to fight with the current champion Ryo Mashiba, Kimura begins to train with Ippo's rival Ichirou Miyata, who previously suffered a crushing defeat from Mashiba's signature Hitman style of boxing. But Mashiba has his own desire to hold onto the belt, hoping to soon shoot for the World title and secure financial stability for his sister Kumi. Will Kimura's overwhelming drive to prove his strength as a boxer overcome Mashiba's desperate wish to provide a better life for Kumi?

The challenger has become the champion as Ippo Makunouchi now wears the featherweight championship belt of Japan. Some time has passed since Ippo's victory, and he has found his friends and coach as supportive as ever; his crush, Kumi Mashiba, seems to enjoy spending time with him as well. Things are looking bright for the new champion, but just as he once set his sights on becoming the best, his first challenger poses an intimidating threat. Kazuki Sanada works as a doctor at the same hospital as Kumi and fights strategically. Known for integrating his knowledge of the human body into his fights, Sanada is a fearsome contender—however, more unnerving than his physical ability, he has garnered the support of the nurses. Despite being the champion, Ippo feels the pressure as he must face the daunting challenge, retain his belt, and win over the girl he loves.