“W-Who are you?” Mu Yu did not have time to pick up the mug on the table as she stood up and took a few steps backward.

“I’m sorry. I must have frightened you,” the man hurriedly apologized to her while taking off his mask. He explained, “Doctor Mu, it’s me.”

“Sir Nie?” Mu Yu let out a long sigh and broke into a smile. “I almost could not recognize you with your mask on. By the way, why are you in the office at this hour?”

“To ...