Ryūmonji Seigō (Hitoshi Ozawa), leader of the Ryūmonji Clan and known as "The Immortal Dragon," leads a double life as "Hide-san," the humble master of a small café. Despite his fearsome reputation, he upholds the yakuza code of honor, solving troubles with his own hands. When Detective Kakuta (Hiroyuki Watanabe) tells him about scams targeting the elderly, Seigō orders an investigation, uncovering that someone within his clan is involved, along with illegal drug trades. “The Ryūmonji Clan must remain noble thieves—protecting the weak.” As his dragon tattoo comes alive, the legendary yakuza takes on modern-day evils!