I was pacing the library out of sheer boredom and lack of investigations. Boredom was making my mind numb when the first pony walked in. I stopped my pacing when I saw the stallion, and walked behind my desk.

"I have a problem." The stallion said.

"Well obviously, that's why you're here at a private investigator's office." I said as though this was common information.

The stallion rolled his eyes and said, "My wife has turned gray and is acting strange."

I stroked my chin with one of my hooves and said, "All right, my assistant and I will check it out." So the stallion gave me his address and I went to get Tina after the stallion had left.

I arrived at Tina's without delay, and we both went to the address that I was given. It was pretty close to Tina's house, so we didn't have to walk much of a distance. The stallion had a nice house, windows and everything.

We walked up to the door and knocked. After being greeted by the stallion, we were let inside. Once in the house, I could hear some angry yelling coming from upstairs.

"She's up there." The stallion said while pointing to the stairs. Tina and I both thanked him as we walked up the stairs. The screaming grew more intense as we went further and further up. We came upon the door that the screaming could be heard from and I opened the door. Tina and I walked inside and saw a mare rolling around on the floor. The first noticeable thing about this mare was that she was completely gray.

I walked up to her and asked, "How are you feeling madam?"

"Awful!" She shouted in response. After my ears had stopped ringing from the extremely loud shout, I felt her forehead. It was burning. I felt her back, also burning. Her stomach was burning as well.

"This mare has an extreme fever, but fevers don't turn a pony gray, at least no form of the fever that I know of." I mumbled.

"How do you know that she isn't naturally gray?" Tina asked me.

I pointed to the mares cutie mark and said, "Her cutie mark has become gray as well. I'm no expert on cutie marks, but as far as I know there are no known gray cutie marks."

"So what does it mean?"

"For now, I don't know. I'll need to think about this." I saw a picture of the mare on one side of the room. In the picture, she was still colorful and she looked quite happy. I grabbed the photo and put it into one of my pockets. Tina and I then left the house and walked back to my office.

Once there, I hung the picture up on a board and began to study it. I sat there for hours trying to understand what the difference was. I just couldn't get it, so I decided to go back to the stallion's house.

As I approached the house, I could hear louder screaming. In fact, it sounded like the screaming was coming from two voices. I ran to the house and barged through the door. On the floor was the stallion, and something was noticeably different about him; the stallion had also turned gray.

I found a picture of the stallion and grabbed it. After putting it in my pocket, I went upstairs to check on the mare, and saw her lying there, still screaming. However, the screaming was growing quieter within time. I could even notice some color coming back into her. This was getting more confusing the further into the case I got. How could this mare be completely sick and grey one minute, and then it spread to her husband the next while the mare gets better in minutes?

Deciding not to be the one to explain this situation to the mare, I left the house and went back to my office. I hung the picture of the stallion on the board next to the one of the mare. I studied the two pictures and tried to find out what the similarities were between the two. All I could come up with was that they were married. I could've come to a better conclusion if I had more information on the two, but I had none whatsoever.

All I knew was that whatever had infected that mare, spread to her husband and left her alone. I began to wonder what kind of disease could do that, but I couldn't think of anything. All I could do was watch this disease spread further, as much as I didn't like it, and gather more information.