When Kage cannot find the way to reach the Underground prison, he decides to ask the zombies he encounters on the way. The zombies tell him where the prison is.
Kage arrives at the prison and manages to defeat the guards at the gate. She sees the prisoners inside and asks them questions, but gets no answers. When the prisoners attack, Kage defeats them and asks again, but again receives no answer.
She decides to ask all the prisoners one by one and kills those who do not know the answer and moves on to the others. Continuing in this manner, only one doomed zombie remains. He says he's been here since the prison first opened, and says he overheard a guard trying to brainwash Sirius.
Kage is angry at what happened to Sirius and prepares to resurrect all the zombie prisoners he killed before and go to where the prison's administrator is. He easily defeats the guards Kagenin zombies they encounter on the way.
They finally reach the manager's office and Kage breaks down the door and enters. She returns to her seat and finds out that the manager is Sirius.
Since Sirius sees Kage as an invader, he takes out his gun and starts attacking. Kage becomes defensive and begins to fight Sirius. They are both quite powerful. After calling the system, Kage detects a virus attack on Sirius' brain.
Thanks to the system, Kage successfully took the medicine, killing the virus in Sirius' brain and changing it back to its original state. During the battle, Kage threw the medicine into Sirius' face, and it quickly took effect.
Sirius collapsed to the ground, screaming in pain as his memories returned. Because the virus had forcibly erased those memories, after their memories came back
Sirius invites Kage to the balcony and says he will help them investigate who did what was done to him. Kage accepts this and they begin to investigate with Sirius. First, they question some of the guards in the Underground prison, but to no avail.
They later find the doctor who performed Sirius' brainwashing and question him. The doctor says that the guards gave him orders and that Sirius must change his consciousness. However, he states that he does not know who hired the doctor.
Kage and Sirius come up with a plan to track down more. The first thing they will do is find out who hired the doctor. Second, the guards need to know whose orders they are acting on. To this end, Kage and Sirius begin to gather information by sneaking around the Underground prison.
After a long investigation, Kage and Sirius finally learn the truth. The doctor who brainwashed Sirius was hired by a criminal organization. The criminal organization wanted to use Sirius for their own benefit after the brainwashing process. The guards were also members of the criminal organization, and after Sirius' brainwashing process, they would make him the leader of the organization.
Kage and Sirius come up with a plan against the criminal organization.