After retiring as the leader of the imperial secret guard, Su Tang is sent by her mother to work as a maid in the Prime Minister's residence. To her surprise, she discovers that the current Prime Minister, Shen Ci, is actually her former junior fellow disciple. Even the servants in the residence turn out to be retired members of the secret guard! She originally intends to settle into her new job quietly, but soon discovers that Shen Ci has been suffering from long-term poisoning at the hands of the Grand Tutor. Su Tang immediately leads everyone in secretly gathering evidence and devising a plan. At a state banquet attended by envoys from various countries, they expose the crimes and successfully bring down the Grand Tutor. After the turmoil subsides, Su Tang remains at the Prime Minister's residence, and affection gradually blossoms between the two. Their days together become lively yet peaceful.