Men of the Underworld: Chapter 4

1st in a 6-film series. The W.R.C. is the largest yakuza-run conglomerate in Japan, and a war for succession begins when the current Chairman suffers a fatal traffic "accident". Tadano (Namioka Kazuki), the secretary to the current Vice-Chair Konno (Noguchi Masahiro), is the only survivor and is haunted by flashbacks. His brother-in-arms, Board Director Umehara (Ozawa Hitoshi), a fellow Zainichi Korean, is in competition with the ruthless Director Tamura (Sugata Shun) for the top spot. The feud is goaded by the secret placement of spies within the WRC by the Tokyo Police's "Unit Zero", spearheaded by the sly Inspector Sano (Shinsui Sanshou), and cracks begin to form in the organization and between brothers ...

2nd film in a 6-part series. Shock and suspicions circulate in the aftermath of the death of the WRC Chairman, and the competition between Umehara (Ozawa Hitoshi) and Tamura (Sugata Shun) begins in earnest. An internal spy was discovered and executed, but rumours of another one circulates the WRC and plagues the guilty conscience of Tadano (Namioka Kazuki). However, the interference of the Chinese Mafia is discovered, and Umehara has suspicions about Tamura's involvement with them ...

3rd film in a 6-part series. Umehara (Ozawa Hitoshi) finds further proof of the internal spy within the WRC organisation's ranks, and moves in to expose the traitor, concerned more with the protection of the organization and his brotherhood than the Chairman's seat itself. Meanwhile, Tamura (Sugata Shun), partners with the Chinese mafia to further plague - if not eliminate - Umehara's faction. Meanwhile, Tadano (Namioka Kazuki), beginning to buckle under pressure, visits the hideout of Yuko (Sasaki Kokone) who is revealed to be part of the mysterious Unit Zero and becomes face-to-face with Inspector Sano (Shinsui Sanshou) ...

The 5th film in a 6-part series. After his beloved Ji-hyun (Otsuka Rina) is murdered, Umehara (Ozawa Hitoshi) hides his grief while searching for the spy, armed now with information from the North Koreans. Tadano (Namioka Kazuki), who is indeed one of the WRC embedded spies, is informed by Inspector Sano (Shinsui Sanshou) that his record in the police database has been erased. Meanwhile, Umehara is arrested by Sano at the scene of a transaction with the Hong Kong mafia, and the goods in question are the trigger point where all factions begin to collide and the truth emerges from the wreckage...

The finale of a 6-part series. Finally, the time has come for the election of the chairman at the WRC executive meeting. Chairman Umehara (Ozawa Hitoshi) was thought to be the sure candidate, but Vice Chairman Konno (Noguchi Masahiro) puts his name forward as a candidate for the position in a surprise move. Chairman Tamura (Sugata Shun) is arrested, but is released by Inspector Sano (Fukimizu Sansho) and sets out to assassinate Umehara. Meanwhile Tadano (Namioka Kazuki) has uncovered the entire truth about his assignment into the WRC, the "accident", and must ask himself: What is loyalty, when your "allies" use you and your "enemies" protect you? A bloody finale ensues!