Shirei to Kisu

Shirei to Kisu summary:

I will destroy your life of mediocrity. A dull and sullen co-worker turns out to be Yamato Toudou -- the super pompous son of a super-rich family -- in disguise!! He forces the unfortunate Shizuku Miyashita to be his slave when she finds herself indebted to him to the tune of 30 million yen! Shizuku had lived an earnest but ordinary life up until this point, so just why in the world did this happen to her?! Wiretaps, disguises, spying... Toudou keeps forcing her to do whatever he wants, throwing her into a panic day after day! But for some reason, she can't bring herself to defy him.... Why is Toudou hiding who he is? A short office love story for young adults by Takashima Eri as a follow-up to her hit series -- I Give You My First!