[Both leads are inexperienced + marriage before love + secret love comes true + feelings develop gradually]
Under pressure from their grandfathers, Lin Shiyue and Jiang Shen get married, agreeing to divorce after two years.
Lin Shiyue feels guilty, believing her presence is standing in the way of Jiang Shen's love. So she loves him cautiously while enduring the hurt caused by his girlfriend.
Jiang Shen pities her for being all alone and gradually gets used to having her around. But a sudden change throws him off balance. He tells himself he needs six months to adjust to her leaving, yet can't help keeping an eye on her moods and feelings.
It takes him a long time to realize that his strange behavior is simply because he's in love without knowing it.