So distraught was Pinkie Pie after being unable to stop Twilight from leaving, so depressed, that she had neither strength nor desire to move from her spot.

When Rarity, Rainbow Dash, Fluttershy, and Applejack each came to visit the library for reasons not related to the pizza place, invariably they’d see the pink party pony laying on the ground and ask what was wrong with her.

Spike would answer that he didn’t know for sure, something about Twilight leaving for the pizzeria never to come back again. The little purple dragon wasn’t sure if Pinkie Pie was right nor not, but he began to worry more and more when his pony mother didn’t return.

No one bothered to try to move Pinkie Pie, as they expected her to get back up again in a matter of hours.

Thus, the pink earth pony remained, sleeping in her spot in the library all that night, and on into the next morning. It was only when she woke up with the sunlight glaring into her face that she finally decided to do something.

The first thing she did was look at the list of ingredients that Twilight Sparkle had gotten from the Griffon kingdom. She wasn’t surprised that the list of ingredients included bear meat, she’d recognized it when she sniffed the pizza. But, unlike Twilight, she was also not surprised that one of the ingredients was cockatrice meat. And, something told her that there would be two more, no, three more types of meat in the pizzas served at that restaurant by now: fox, rabbit, and pony.

Pinkie Pie was about to leave the library for the first time since her last conversation with Twilight, when Spike came downstairs and asked, “Pinkie Pie, has Twilight come back yet?”

The pink earth pony looked down, shook her head slowly, and said, “No. Don’t you remember? She’s not coming back. Not alive anyway.”

The purple dragon glared at Pinkie Pie and said, “Hey, that’s not funny.”

At that point, Pinkie Pie turned and galloped the few paces to the little purple dragon, grabbed him, and held him in a tight hug.

For a moment, Spike was confused. Then, he pushed away from Pinkie Pie and said, “That’s enough. You’ll see. Twilight’s coming back. And, she’s coming back alive.”

But, the pink earth pony refused to let go of him.

Spike finally managed to struggle out of Pinkie’s grasp by moving under her forelimbs. Then, pushing away from her, he said, “I mean it, Pinkie. There are things I need to do. I have books to put away, parchment and ink to set up, a meal to prepare, and a library to keep in general order. Either get out, or help me.”

Pinkie Pie said nothing, just went out through the front door and slowly made her way home. Once there, she locked the door behind her and went to her bed. Her grief over her lost alicorn friend was far greater in her than any need for food or sleep. All she could think to do was wait for one more nighttime, so she could investigate the Pegasa’s Pizzeria, and maybe complete the work Twilight had started.

That evening, Pinkie Pie got up out of her bed and made her way outside and to the pizzeria. Once there, she gently pushed on the door, and it opened on its own. She made no sounds, she didn’t feel like making any sounds anyway.

The door automatically closed behind the pink earth pony once she was completely inside, somewhat startling her as the metal of the door made contact with the metal of the stop on the side.

When Pinkie Pie realized she was the only one inside the building, she sighed with relief, then started exploring the now vacant restaurant. She sniffed at the displays in the theater, explored the ovens in the kitchen, tested the cash register, sat on benches and chairs and tapped on tables.

The one thing she didn’t expect in an empty building was to hear the quiet voice of her yellow pegasa friend, Fluttershy, ask, “Pinkie Pie, what are you doing here?”

For the first time since her last conversation with Spike, the pink earth pony vocalized. Before she could stop herself, she let out a split-second shriek. Then, covering her muzzle with her hooves, she turned to the yellow pegasa and said, “I heo—“ Realizing her inability to talk through her forelimbs, she put them down again before trying again: “I’m here to continue Twilight’s investigation of this place. Something’s not right here.”

Confused, Fluttershy asked, “Continue? Did something happen to Twilight?”

Pinkie Pie sighed deeply, then said, “I’m sorry to have to tell you this, Fluttershy, but Twilight’s been killed.”

Tears welled up in the pegasa’s eyes as she covered her mouth with her forelimbs and gasped. When she put her forelimbs back on the ground, she asked, “Are you sure, Pinkie?”

Pinkie Pie nodded as she answered, “Yes, I’m sure. Whoever opened this pizza place has been killing your friends, Fluttershy, and now she’s killed Twily, too.”

Fluttershy stammered for a moment before asking, “Do you have any proof?”

The pink earth pony answered, “Not yet, but I’m running out of places to look. Wherever the evidence is, I’m sure to find it if I just keep looking.”

Fluttershy said, “Well, I don’t like the idea of you breaking into places where you shouldn’t be. But, if helping you search for clues is the only way to satisfy you so you’ll leave, then I’ll help you.”

Pinkie Pie looked away from her yellow pegasa friend as she said, “I’ve already checked the theater, the kitchen, the front room, and the bathrooms. You know, I never knew ponies could be so messy.”

Fluttershy pushed open a nearby door as she asked, “You haven’t checked the basement yet?”

Pinkie Pie immediately turned to her yellow pegasa friend and, in surprise, asked, “This place has a basement?”

Fluttershy backed away and asked, “Doesn’t Sugar Cube Corner have one?” After a step or two, she stopped and added, “Every building like this that's in the business of serving food has a basement.”

The pink earth pony accepted her yellow pegasa friend’s outstretched forelimb as an invitation to head down the stairs into the dark lower level. On the way down, she said, “You know, Fluttershy, if there’s any—aghh!” Before she could say another word, she suddenly felt a strong, painful force on her backside, which forced her to fall forward down the stairs. At some point in her tumble, she heard a cracking sound which made her feel like something had definitely gone wrong. She couldn't immediately explain it, she just felt as though her head was suddenly trapped by something; and it scared her. She began to struggle, but then she felt something prevent her from breathing properly. And, the more she fought, the more certain seemed her chance at failing to escape; but still she struggled. With all her strength she wrestled with whatever it was that was keeping her head lowered, until she finally collapsed, and waited for the inevitable.

Minutes passed by before she found herself able to move again, and she was surprised because, in spite of having limited ability to move before, she was completely able to do so now. Even more surprising, in spite of how dark it was in the room, she could clearly make out objects in the basement … including her purple alicorn friend. But, there was something … not right about her. For that matter, there was something not right with Pinkie Pie, something more not right than usual.

Twilight was frowning as she said, “You too, huh Pinkie?”

Pinkie turned and looked down at her body, her neck bent in an unnatural angle, an angle that would make it impossible for her to breath. And then it dawned on her. Looking up at her alicorn friend, Pinkie Pie asked, “I’m dead, aren’t I?”

Twilight nodded and answered, “You and me both.”

Pinkie started to cry as she said, “I’m so sorry, Twily. I just wanted to keep your investigation going.”

Twilight nodded and said, “And, you did well. I’m happy to see that you took something from your experience with that MMMM cake.”

Pinkie Pie snorted as she said, “Yeah, and a lot of good it did me.” And, before Twilight could say anything more, the pink earth pony added, “I knew you weren’t coming back alive, and I knew something was wrong with this place. But, how could it have been … ?”

Twilight took a step toward her pink earth pony friend and said, “I know how you feel. She betrayed me just as much as she betrayed you. But, now we’ve got to make sure she doesn’t do anymore damage.”

Pinkie Pie sniffled once more before saying, “You’re right, Twily. So, where do we begin?”