"Are you saying you weren't the one who secretly put graphite in our backpacks?" The doctor shifted his gun toward Zhang Heng.
"That's right," Zhang Heng said calmly.
"That's impossible," the doctor said flatly. "Everyone's physical condition except yours is deteriorating rapidly. If you weren't the one who put graphite in our bags, then all he accomplished was benefiting you. That makes no sense at all."
"It really doesn't make sense," Zhang Heng agreed with a nod.
Surprise appeared on the faces of Kratos and the other players. They had not expected someone to admit it so readily. Then Zhang Heng continued, "Unless... the person who secretly put graphite in your bags wasn't a player."
"Not a player... what does that mean?" Mouse asked, puzzled.
The doctor said, "After we split up, Mechanic and I drove straight out of Pripyat. We were very cautious along the way and avoided contact with outsiders as much as possible. I can be certain that no one touched our bags during that time, so that piece of graphite was already in the backpack before we separated. At that time, all of us were together. Other than our own group, no one could have slipped something into our bags without us noticing—unless that person was completely invisible."
Zhang Heng ignored the doctor's final jab and merely asked, "Do you remember the name of this instance?"
"Invisible Killer? What's wrong with that? Didn't we already conclude that the Invisible Killer refers to Nuclear Radiation?" Kratos said.
"Nuclear Radiation does fit the definition of an Invisible Killer. Besides, we encountered a nuclear explosion the moment we entered the instance, so naturally we were inclined to think in that direction. At first, I also tried looking for answers from that angle, investigating the cause of the accident step