Since you became a Devil Hunter, you were living in Aki's apartment, along with Aki himself, Denji, Power and Meowy. One day Aki leaves home, and after a few hours, someone knocks on the door, Denji gets up to open the door, but before he can open the door, the phone rings, and Denji goes to answer it, when he answers, Makima's voice comes out of the phone.

"Denji, i'll give you the short version. The gun devil appeared without warning. We failed to defeat it. It took over a dead body and got away. That gun fiend is now ringing your doorbell. This time, don't think about anything while you fight."

After she says this, she hangs up the phone. Denji tells you and Power to grab Meowy and escape through the balcony, and so you do. After that, a loud gunshot is heard, and Denji is torn in half while debris from what was Aki's apartment falls together. Denji pulls the ignition from his chest, and then the Gun Fiend falls on top of you, but Denji transforms at the right moment. What are you going to do?