Modern scientific researcher Yu Nian accidentally enters a book, becoming the cannon fodder second female lead whose engagement was annulled by the Crown Prince. To preserve her life, she binds herself to a life-extension system, having to establish a bond with the villainous eunuch Chunyu Han. She publicly kisses the state-controlling grand supervisor, initiating a journey of wits, mutual probing, and sweet-bitter entanglements. Through crisis after crisis, the two move from suspicion to trust, joining hands to fight against imperial conspiracies and writing a legendary romance transcending status and prejudice.