To escape an arranged marriage orchestrated by the Jiang family, Su Nian randomly signs a 90-day sham marriage agreement and recruits Lu Shen, a seemingly ordinary man, to play along. At a banquet, he steps forward to protect her. In their daily lives, he looks after her at every turn and effortlessly resolves business crises, while his true identity remains shrouded in mystery. An accident three years ago secretly connected their fates. Lu Shen has been protecting her in secret ever since, but fearing that gratitude might become a burden, he has never revealed the truth. Jiang Yu, her best friend Lin Xi, and powerful business tycoons take turns plotting against her. As the 90-day deadline approaches, Su Nian uncovers every hidden truth, tears up the exit agreement, and takes the initiative to sign a marriage contract with no expiration date, choosing the man she truly wants to spend her life with.