Silver Fang.

According to the note, Princess Twilight Sparkle will back to the castle with her new husband, Silver Fang , a day after their marriage ceremony in Canterlot.

“That ceremony was yesterday. The castle and the crew will be ready for old and new residents, just on time”, thought the captain of palace guard, Double Diamond. He was responsible for pushing things in motion here, and he knew what he was doing.

All Equestria was happy because the youngest princess found her special somepony. He even more than others, because he knew the bridegroom personally.

The white pony placed his rump behind the desk. He was in his office,  with a cup of a excellent tea. He had got some time before everypony will come to welcome newlyweds, so he sink in his memories.

He was only a sergeant when Princess Luna decided to send his small unit as  personal guards of the “elements of harmony”, during the last King Sombra’s crisis. But he didn’t manage to be on time before elements of the harmony departed from the train station because Princess Celestia had burdened him with tonnes of paper work. She did that knowing that papers could wait. His soldiers went without him and, as it turned out later, they had helped nopony.

When Princess Luna had been informed about that, she almost exploded in face of her royal sister, but everypony knew that nuzzling around royal private matters never was a good idea. They paid the guards for obedience, not for thinking.

That’s why after the promotion to captain Double Diamond was so happy that princess Twilight Sparkle was considering everypony as her closer friend. Not everypony was close, of course, but concept of being friendly with somepony’s servant, was melting captains heart everytime. A friend. Not a living tool.

He took a little sip of still warm mixture, and felt how delicious this tea was. Its taste reminded him a wild nettle mixed with mint and citrin. Heaven in his mouth. It was a special gift from Zecora the Zebra. He had helped her once in a very common case, he even wasn’t able to remember what was that, but after that, once a week Zecora sent a little filly, Apple Bloom, if he was correct, to him with her expression of gratitude, and that meant, with some bags of herbs.

Taking another  sip, he relaxed on the chair like  only someone who was happy of his life could.

Recollecting more memories, captain Double Diamond backed to that feral day when he alone landed on the cursed land of Crystal Empire.

He would never find a way to the city if he had not met at Silver Fang.

His mane was silver, and he was a crystal pony, and he had got the greatest piece of metal captain (then sergeant without his unit) had ever seen. It turned out it was his greatsword.

Yes. Pony with a sword. That was peculiar, but since nopony else but Double Diamond was on the station, he asked him about the way.

They quickly found common ground. He was a soldier of Crystal Empire, and sergeant Double Diamond was a soldier of Equestria.

Another sip, another memoir.

This same day he and the bridegroom became  brothers in arms, if running away from corrupting black fog could be considered as fighting.

“Anyway, White Fang showed that his will was strong as his steel, and now he became a prince of Equestria”, captain thought.

Double Diamond finished his tea, which was cool already, but still remained tasty. He knew that the time was short, so he wiped his hooves and put his armor on. When he had done that, he went out his  office, which was between barracks and the castle.

The day was beautiful. The sun was high, birds were singing and there were no cloud on the sky. Everything was going just fine. It was sensible that even mother nature tried to celebrate with ponies. That was a good sign, because Rainbow Dash, the weather pegasus, was coming back with princess and prince, so she couldn’t help.

Coming closer to the castle he saw small delegation formed by everypony in Ponyville! They all were waiting to cheer for their beloved ruler and her husband. It was out of the plan, but it wasn’t surprising. The Mayor mare had said that there will be only couple of most important ponies, but, heh, everypony loved their princess. No one could blame them for happiness and curiosity.

The crowd was excited, but  peaceful. There was no crime in Ponyville. There was no need to use physical power in last… well, since Lord Tirek ran away from Tartarus.

Other guards saluted to their captain, but it was visibly they were a bit too hyped than they should be, too. The atmosphere chipped in Captain and Mayor mare, eventually.

It was big day, and nothing was able to ruin it. “Yesterday was special for Equestria and for Crystal Empire, but today is even more special for everypony who personally knows princess,” double Diamond thought, “and everypony knows her.”

And he was right, because on this evening the biggest party that Ponyville remembered was planned.

But the princess and her new husband didn't come on the time. The crowd was impatient, epeciall when the sun was high.

Something had to stop them, but what exactly?