After touring the gloomy, oppressive cell blocks and the office buildings surrounded by high walls, Mui had just led Yūto, Tsunade, and Yíngsháo out of the last building.
Mui had deliberately avoided the most secret area deep within Hozuki Castle, where the Box of Ultimate Bliss stood. He did not want to head straight there at the outset; that would make his intentions too obvious and arouse suspicion.
He was just about to make some polite conversation to ease the heavy atmosphere the prison had created.
Just then, a guard rushed over in a panic, stopped before Mui, and shouted breathlessly, "C-Castle Master! Something terrible has happened! Young Master Muku... Young Master Muku is missing!"
The gentle smile on Mui's face froze instantly, then gave way to anxiety. "What?! You said Muku is missing?!"
He gripped the guard's shoulders tightly. "Where did he disappear? When did it happen?! Find him! Now! Seal every entrance and exit, and thoroughly search every place someone could hide!"
He practically roared his orders, his voice filled with a worried father's fear.
The guard flinched at his violent reaction. "Y-yes, Castle Master!"
Then he turned and ran off to gather more men.
Mui drew a sharp breath, pretending to struggle to suppress his fear. With deep apology on his face, he turned to Yūto and Tsunade:
"Lord Yūto, Lady Tsunade, I am terribly sorry. My son has probably run off to some corner to play hide-and-seek... I won't be able to accompany you any further."
He bowed slightly and made to leave to search.
Mui was already planning his next move: how to naturally ask Yūto for help once the guards failed to find Muku, luring him into that dangerous area.
This opportunity had to come naturally.
Yet at that moment, someone unexpected stepped forward.