Lou Jia, a recent graduate with a master's degree in languages, volunteers as a teacher in the remote Wutong Village in Linnan Province. The harsh rainy season isolates the village, making travel nearly impossible. When the only male volunteer in her group injures his arm and leaves, Lou Jia’s friend Jian Rongrong arranges for her stepbrother, Jiang Siwei, to fill the vacancy. Jiang Siwei, who had moved to the United States with his mother after his parents divorced and later attended boarding school, arrives after a grueling three-day journey through treacherous mountain roads during a storm. Lou Jia, who raised him somewhat after their parents remarried, views him with a mix of sibling affection and mild exasperation at his recklessness. Their relationship is complicated by the fact that Jiang Siwei is not her biological brother, a detail that becomes increasingly significant as the story progresses.
Jiang Siwei’s arrival disrupts Lou Jia’s quiet routine. He is no longer the shy, quiet child she remembers but a tall, handsome young man with a reserved demeanor. Despite his awkwardness in social situations, he shares a deep, history-laden bond with Lou Jia. Flashbacks reveal that when their families first merged, Jiang Siwei felt like an outsider, particularly due to Jian Rongrong’s hostility. Lou Jia was the only one who showed him kindness, making him noodles and ginger tea when he ran away from home in the rain. This act of compassion created a profound attachment in Jiang Siwei, who secretly dreamed of being adopted by her family. As he entered puberty, his feelings shifted from sibling-like dependence to romantic love, causing him to withdraw and avoid her during high school. He left for university and then abroad, maintaining only distant contact, until Lou Jia’s casual mention of needing a substitute teacher prompted his return.
The core conflict emerges when Zhang Lin, Lou Jia’s college boyfriend and the person who organized the donation supplies that brought Jiang Siwei to the village, arrives to see her. Zhang Lin still harbors feelings for Lou Jia and hopes to rekindle their relationship, viewing her as a calculated choice he can revisit. Jiang Siwei, witnessing Zhang Lin’s return and Lou Jia’s polite but distant interaction with him, becomes visibly distressed. He struggles with jealousy and insecurity, fearing that Lou Jia might return to her past life and leave him again. His internal turmoil is exacerbated by his inability to express his feelings openly, leading to periods of silence and avoidance.
A key turning point occurs when Jiang Siwei falls ill with a high fever after his difficult journey. Lou Jia cares for him meticulously, and in his delirium, he cries and clings to her, revealing his vulnerability. This moment breaks down the barrier between them, allowing Lou Jia to see him not as a child but as a man. Later, during a group camping trip, Jiang Siwei confesses his love to Lou Jia under a sky full of fireflies. He admits that he has loved her for years and that his hesitation stems from fear of rejection and the belief that he is not good enough for her. Lou Jia, surprised but touched, does not immediately accept or reject him. Instead, she asks for time to process her feelings, acknowledging that her view of him has changed but that she needs to let her own emotions evolve.
As the story progresses, Jiang Siwei’s affection becomes increasingly obvious to everyone around them, including Jian Rongrong, who initially opposes the relationship but eventually comes to accept it. Jiang Siwei’s actions, such as creating a rainbow for the students and posting a photo of Lou Jia with the caption "What I like," signal his commitment. Lou Jia begins to reciprocate his feelings, engaging in playful interactions and showing concern for his well-being. The narrative concludes with the two of them navigating the early stages of a romantic relationship, set against the backdrop of their volunteer work in the village. The rain eventually stops, symbolizing the clearing of obstacles and the beginning of a new chapter in their lives.
