Kai, also known as Secret Gardner, is a professional bodyguard working for OGA's Secret Service SCS, protecting clients ranging from government officials to ordinary citizens. One day, the son of his client, corrupt lawyer Kozo Samejima—Shota—is suddenly kidnapped. Kai tracks down the kidnapper, rushes to the scene, engages in a fierce battle, captures the criminal, and safely rescues Shota. However, instead of expressing gratitude for his son's safe return, Samejima verbally assaults Kai and slaps him. Witnessing this, Kai instinctively punches Samejima in retaliation. Expecting severe punishment, Kai is instead asked by Samejima to guard his son. But this is merely a trap. Samejima plans to use his own son as a tool for revenge, orchestrating Kai's complete humiliation. Unaware of Samejima's true intentions, Kai gradually lets his guard down, drawn in by Shota's innocent curiosity—exposing himself more and more. As a result, he becomes entangled in an unforeseen and devastating chain of events… [BAD END]