5 years and 6 Months Before Cadence’s Death (October 10)

        Luna was walking to a part of Equestria unknown to all but those of the Royal Family, which included Twilight Sparkle, Shining Armor and Cadence, Celestia, and herself. Ahead of her was a large metal gate that measured at least twelve by twelve feet, if not more. Luna muttered something in Ancient Equestrian and the gate opened. It was in fact an entrance into Tartarus and Luna gulped before she inhaled a calming breath and stepped within. The gates closed behind her with the sound of metal creaking loudly before they closed entirely. Ahead of her, the princess of the night saw Cerberus shaking in fear, though whether it was of her or something else was unknown.

        I wonder who could have made Cerberus of all creatures scared, she thought.

        She turned and trotted to a nearby mountain, an expression of serious determination on her face. As she approached the top she saw a prison. At first she froze in her tracks as she observed it, but remembered why she'd come to this place to begin with and so continued her approach. Recently a pattern had been forming; Chrysalis disappearing , followed by Discord's disappearance a month  poir. Her informant in Ponyville also noted that a Starlight Glimmer that Twilight had faced in battle, also vanished, but she had something with her in the battle, Star Swirl's time spell which she thought was under lock and key . From this, Luna suspected somepony or something was gathering all the past big villains that the Elements of Harmony had faced and had a hunch her trip would confirm her suspicions.

        When she finally reached the prison, she saw Tirek’s robes and when she looked under them there was only a pile of ashes remaining. She then noticed a stretched out writing on the floor of the cage that read “The Master” and saw another on the ceiling of the cell reading “Obey The Master”.

        Luna took a camera out and started to take pictures of the scene. When she got back to Canterlot and got her pictures ready she took out her cassette and started to record an entry.

        “Today, I learned that I was wrong about one suspicion: the villains aren’t banding together to take over Equestria, because today I've found out that Tirek was reduced ashes with writing left behind in his former cage. Whoever this ‘Master’ character is, they scared Tirek. It appears to me that he may have possibly worshipped 'The Master' as a god of some type.”

        After she was done recording her entry she put the pictures on a bulletin board of all the evidence and research that she, Night Light, and few other had gathered so far.

        ~

        2 weeks later

        As Luna was walking along her usual route through the castle, she noticed her Night Guard commander was scrambling her soldiers and answering some serious questions. The princess trotted up to to them.

        “I'd like to know what is going on here,” she said.

        “Sorry Luna, but we just heard from your sister that Rainbow Dash, the former holder the of the Element of Loyalty, has disappeared,” the commander reported.

        “And what are you doing about this?” she asked.

        “I've sent messengers out to retrieve some other soldier stationed around the city to meet up with me so we can formulate a search and possibly rescue party,” she explained.

        “Very well then,” Luna replied, “Carry on.”

        She walked away after that, heading to the throne room. The fact that Dash was missing weighed heavily on the princess's mind. It was a disturbing revelation.

        “Why would Rainbow Dash disappear without notice?” she contemplated as walked through the castle, “She represented the Element of Loyalty for a reason. She wouldn't just abandon everypony that she cared about without cause.” Luna recalled the dreams she traversed the nights before as she thought about the cause of the disappearance. “She had no obvious intentions or thoughts patterns about running away that I could glean. If they do find Rainbow Dash, I’ll need to ask some questions.”

        ~

        5 months later

        After months of searching, a pair of pegasi had found Rainbow Dash on an island, but wasn’t good news. They found her dead with severe burn marks on her chest. It was a sad day for Twilight, and it was a first for her as well. She'd never been to funeral in her life nor had anypony close to her ever died. Luna felt sorry for her, so later that night she'd planned to travel into Twilight’s dreams to help ease her mind, but was interrupted by the young alicorn's father when he suddenly came running in to see her unannounced.

        “I'm sorry your highness, but you need to see this...” he panted.

        Luna and Night Light hurried to the forensics lab and when they arrived there Luna was confused at the sight of a changeling on the autopsy table.

        “I'm confused detective,” Luna said, “Please explain why there's a dead changeling on the table.”

        “Well I, uh...” he said with a nervous laugh, rubbing his head, “I...dug up Rainbow Dash’s grave.”

        “Why?” Luna asked.

        “Well the whole thing is odd. Dash found on an island with no inhibits and no ancient ruins?” Night Light, “She wouldn't have stayed there long even if it's true. From what we know she likes to brag about her accomplishments and there was reportedly nothing noteworthy there.”

        “Not we know of,” Luna replied, “But I've been meaning to investigate that island myself. Rainbow Dash's body actually being that of a changeling means that Equestria was fooled.”

        “Could it be Queen Chrysalis who did this?” Night Light asked.

        “Not likely,” Luna replied, “This isn't her style.”

        “Then who could have put a changeling decoy on that island?”

        “I'm betting the same thing that killed Triek and the Changelings.”

        “Wait Tirek is dead? How do you know?”

        “I went to his cell a while ago and found his body reduced to nothing but ash, with the Master’s name written out on the cage's floor and ceiling.”

        “So the Master, whoever it is, faked Dash’s death? Why though? Should I tell my daughter that her friend is alive, maybe?”

        “Why indeed Night Light?” Luna asked, “But no, not until this mystery is solved. If and when that happens then maybe we might find Rainbow Dash alive and then we can tell your daughter.”

        “I'll continue to investigate this Rainbow Dash imposter and why something or somepony would want to bury a decoy then. While I do that, it should give you some time to investigate the island they were on.”

        “Agreed. I'll round up some ponies to take with me there.”

        “Good Luck.”

        “Likewise,” Luna replied with a nod.

        ~

        The following morning, Luna had a couple of chariots prepared for the trip. She rounded up the ponies she planned to have accompany her, totaling about thirty overall.

        “Thank you for taking me, I mean us,” River Fang, one of Lunar Highest Guard, said.

        “You’re very welcome,” Luna replied, “Ponies from your group are the ones who found Rainbow Dash. You have more experience on that island then anypony, including myself.”

        “I found the island a bit creepy your highness,” Sliver Fang admitted, getting on the carriage with Luna, “I felt like I was being watched.”

        “I’ll take note of that,” Luna assured before she gave the signal for take off.

        The trip took about a few hours or so. River Fang went on about how his daughter was the biggest fan of the princess and they shared a few laughs. When the island was in sight, Luna saw that Sliver Fang took a deep breath, but was shaking. She too felt a sense of dread at the sight of the place.

        “What is it Luna?” a bat pony by the name of Ether Night asked.

        “It’s just as Sliver Fang said, but I also sense despair and terrible suffering here,” Luna said, “Come on, as old friend of my fine once said: Allons-y; but keep an eye out.”

        “What does that mean?”  River Fang asked.

        “It's fancy way of saying 'Let’s go.'”

        They moved forward into the island jungle. The group hiked for a good while until they found a building of some sort. It look fairly new, despite some growth slowly creeping along its walls.

        “This looks recently built,” Ether Night observed.

        “Which worries me the most,” Luna said, approaching the entrance, “How and when did this get built?”

        They entered the building only to find it completely abandoned.

        “This makes no sense Luna, why abandon a building that was just built?” another bat pony by the name of Night Sky questioned.

        “Night Sky, Ether, take a squad of my guards with you,” Luna ordered.

        Night Sky took a small squad of her guards with him and so did Ether. They went in opposite directions of one another – left and right respectively – while Luna and the remaining ponies went straight. They searched carefully with every step, but even while they did Luna couldn't shake the feelings of great torture and sadness that seemed to permeate the very air. They reached some stairs and proceeded upwards. Luna used her magic to open a door at the top and noticed they entered an observatory room on research subjects, or possibly a control room; it was hard to tell due to everything looking burned and papers scattered and charred too much to read. She looked around on a desk for anything that might shed light on what had happened, but heard a clicking sound behind her and turned around. She saw that her guards, including River Fang, pulled out a crossbows on her with some having dark magic spells imbued on the bolts or at the ready crackling from horns.

        “What is the meaning of this?” she demanded.

        “Well you see Luna this is a trap,” River Fang stated moving forward, “As of right now my fellow guards are about to kill your 'children.'”

        “Why are you doing this Silver Fang? What about your daughter?” she asked.

        “All a lie, a cover,” he stated, “I'm the Master’s top spy, a mole if you will, that's been posing in the Lunar guard.”

        So it’s a he, Luna thought before she spoke aloud, “I'm guessing he has at least one in the Solar Guard as well?”

        “Yes, and there are plenty of ponies who worship him, more than you and your sister,” Sliver explained with a malicious grin, “and he knows about your little investigation into him. Before you ask, he’s pony like you or me, but you’ll never guess who he is.”

        “You’ll pay for this treachery,” Luna replied, “But I have one question: why?”

        “Orders from the Master; he wanted to lure you here. How else would you know of this island’s location?”  River Fang moved to the control panel in the room and unlocked a hidden button using key, “He has big plans on the way and you two are getting too close, so the best way to stop you is to separate you all as far as possible and take you out.”

        River Fang pressed the button, which caused a large explosion somewhere and made the entire building heave, throwing everypony off their hooves. In the confusion, Luna blasted a few of the ponies with magic to get them out of her way and started to run as the building was beginning to fall. She heard Sliver yell at his followers to stop her and kill her. She ran as fast as she could and got out of the building while her own guards – defected now – were firing at her with dark magic and enchanted crossbow bolts. Barely escaping, it didn't take her long to notice that the surrounding vegetation was engulfed in flames. There was an opening however, a cliff that overlooked a drop into the sea several yards below. Luna galloped for it as fast as she could and dove off. On the way down she spread her large wings, using the velocity of the fall to boost her flight speed as she pulled out of the dive further below. She flew away from the island, her wings carrying her swiftly to Canterlot.

        Despite her fast flying, Luna still didn't arrive until after sunset. The moon had already been risen, probably courtesy of her sister. The night princess landed to catch her breath, but she noticed a thick column of smoke rising in her peripheral vision. It was coming from the forensics lab where she'd left Night Light to do the autopsy on the changeling's body.

        “No, no!” Luna cried, running to it because her wings were too tired to get her airborne again.

        When she got there, she noticed several ponies in shock, and faces awash in horror. There was a conversation going between some of the guards as the alicorn approached.

        “We found their bodies,” one of them said.

        “Who was it?” another asked.

        “Night Light and Twilight Velvet,” a third replied.

        Luna arrived on the scene then and the conversation ceased altogether. Though the entrance was barred off by police tape, there was no disguising the grisly scene within; two ponies wholly slaughtered in what appeared to be some sort of struggle. The bodies were in separate body bags now as police and investigators gathered evidence from the scene, but blood still painted the floor and other surfaces crimson, and the stench of death lingered in the stagnant air.

        Luna hurried away from the scene and went to her quarters. She was thankful to find her chalkboard, files and cassette tapes remained intact, but it did look somepony had started ransacking her room searching for something, perhaps the records of her findings, but had probably hurried out before they could get very far, which explained why only a portion of the large bed chamber was in chaotic disarray. She decided only a few trusted individuals should know about her investigations. If she'd told Twilight that Dash might be alive out there somewhere as Night Light has suggested, it would have jeopardized everything she'd been working for and possibly put Twilight in danger as well. Luna took out her cassette tape recorder and started a new entry.

        “Myself and Night Light were set up tonight and paid a heavy price for it. He found out that Rainbow Dash's death had been staged, and a changeling was buried in her grave. Because of this, I left with ponies I assumed to be trustworthy on an expedition to the island where she'd supposedly been found. On the island, I was betrayed by one of my best guards in a seemingly abandoned building that had appeared to have been recently built: Silver Fang, an agent of a male pony known only as 'The Master'. He revealed that ponies on both the night and day guards, and I suspect possibly others outside the military, worship him. As I stand here right now thinking and recording this entry, I'm left to wonder if Night Light had already figured out who the Master was. If so that would explained why he was murdered, along with his wife who was working in the lab at the time. If Night Light did figure something out, that information is lost to the grave. I do swear on my own life however, that I will figure who the Master is, and bring him to justice.”

        She stopped the recording and walked to the bulletin board she had set up. Pictures attached to it formed of spiderweb or criss-crossing strings tied around tacks connecting everything on some way. On a card, Luna scrawled out the words 'The Master' in the center. In the spider web pictures of Changelings, of the island, the fake Rainbow Dash, and Tirek’s ashes surrounded it. With her magic she also added cards with the words 'Solar and Lunar Guards' connecting to a few key names as well as questions like 'Betrayal?' and 'More possible spies?' and also 'Night Light and Twilight Velvet' along with the word 'murdered' and 'possibly figured out 'Master's' identity' and used some more yarn in the spider web connecting them to the name at the web's center; the poisonous spider at the heart of it all.

        Who are you? she thought to herself, looking at the board.

        ~

        The funeral was the following weekend. It was for both of them and Luna had never seen Twilight or Shining Armor so upset before. She couldn’t blame them however; they had every single right in existence to be so miserable. The night princess gave her words of condolence during the funeral but had to leave soon after due to a prior engagement. After a while, a small number of bat pony guards entered the room she'd set up for the meeting.

        “You summoned us, Luna?” one of them asked.

        “Yes, I did,” she replied, inviting them in to sit down, “I was nearly killed about a week ago on trip to the island where Dash was found dead, and by those whom I thought to be trusted guards no less.”

        The faces of the other ponies ranged from disgust to horror, with some a mixture of both.

        “The reason why I was betrayed was because I believe Night Light and I were getting to close to finding out the identity of the Master,” Luna continued, “I also learned from the traitor that there are spies in Celestia's daytime guard as well.”

        “So what’s to be done?” another of the bat ponies asked, clearly frightened.

        “Was Night Light killed because he went insane as the rumors say?” a third asked.

        “As I've already said, no, he wasn't killed because of his insanity. That is a blatant lie and I highly suggest you banish such notions from your minds. The Master is covering it up somehow by either brainwashing the guards and/or press. The Master wants me to stop my investigation according to what one of the traitors told me. Night Light's and Twilight Velvet's deaths shall not be in vain however, and I will not let them go unpunished. The investigation into the identity of the Master is still ongoing and only between us. Understood?”

        “Yes, Luna,” they all replied.

        “Dismissed,” she ordered.

        As they left, she then went to look outside at the ponies below through the window. Even with such a pledge she knew she had to keep her guard up at all times.

        “I can’t trust anypony now it seems,” she whispered to herself.