Traitor!! In the palace

The castle was bustling with people. Guards stood at every doorway. Friends from far away had come to celebrate the coming of spring.
Stephan knew he should be with his guests, but he had more pressing matters on his mind. He waved a hand at one of his guards, who was at his side in seconds.
"Your Majesty"
"Get me Alastor.", Stephan ordered.
"At once sir."
'I have to see him.' Stephan thought. 'He hasn't reported to me in over a week. Something must have happened.' He hoped that he was stressing over nothing, that Alastor had just been too busy to report back, or perhaps he had good news, maybe there had been some sort of breakthrough. 'No, he would have reported to me immediately if he had good news.' Voices from behind distracted him from his thoughts.
"King Stephan! It's nice to see you again!" For a second, he didn't recognize who he was looking at, but then he remembered.
"King Nickolas, Neomi. It's a pleasure to see you." They were the last people he wanted to talk to, but he stayed polite. He couldn't let someone like Nickolas or his feeble-minded wife see that he was troubled. Who knows what kind of rumors they'd spread.
"This is such a splendid party, it was so kind of you to invite us." Neomi smiled.
"Please, you honor me by coming." Stephan could see Alastor making his way through the crowd behind Nickolas.
"Pardon my rudeness, but there's someone I must speak to. It truly was a pleasure seeing you again." He quickly made his way to Alastor, not waiting for a response.
"Your Majesty. You called for me?"
"Yes. Why haven't you reported back to me? Your last check-in was a week ago.", Stephan questioned.
"Your Majesty, we should talk about this after the party."
Stephan grabbed Alastor and dragged him into his study, hoping that no one saw him.
"Tell me. NOW!", he ordered. Alastor flinched slightly.
"We had a slight complication. But it's being resolved."
"What kind of complication?"
"It's under control, sir-"
"WHAT KIND OF COMPLICATION!", Stephan demanded.
"O-one of them escaped sir, #7."
"Were there any casualties?"
"Four, sir," Alastor looked down, knowing Stephan would be furious.
"Four guards!? How could one brat kill four trained palace guards?! Are you kidding me!?"
"They're a strong one, sir. This hasn't been the first time they tried to escape. But it's taken care of. I assure you, this will not happen again."
"Where is it now?" Stephan would have liked to just kill the brat and save trouble, but he knew that they needed them. #7, the strongest of his group, and the only one still alive.
"They're sedated. They put them with the others." Stephan sighed.
"Ok. What about the cure?"
"Sorry, sir. We haven't gotten any closer."
"Well, work faster!", he snapped. "And tell me when that brat wakes up." With an aggressive wave of his hand, he dismissed Alastor. He no longer wanted any company, neither did he want to entertain his guests. So he locked his door and sat heavily on his chair, letting his bitter thoughts consume him. 'Filthy scum! Mutants! They think they can curse us with diseases and get away with it!? Haa-! I'll show them. They're gonna regret ever setting foot on my kingdom. I'll find the cure. And I'll make their life a living hell as I do it!'
He looked up at the family portrait on his wall. He would do it for them. For his beautiful wife, who they took from him! And his lovely daughter who was all that he had left. He would find the cure, even if he had to lose his sanity to do so.