Nicholas William had been following Dean Bruce all day long and had never once separated from him. Logically speaking, if Nicholas had fallen into a trap, then Dean Bruce shouldn't have been unaffected either.
After pondering for a moment, Dean Bruce finally identified the cause.
The food and wine served at the banquet!
Dean Bruce hadn't taken a single bite of food, and when people tried to toast him, he skillfully evaded by steering the conversation elsewhere!
The medium must have been the food and wine. That's the only way Nicholas could have been affected despite the considerable distance from the one in the shadows.
[In that case, the mastermind must be Miranda Joy or Prani Joy. They're the only ones with authority over the royal court.]
[Another suspect is the Gold family, which controls the entire Imperial Guard. They could have easily tampered with the banquet.]
