The fourth episode of "Had I Not Seen the Sun" commences with Hsiao-tung and Jen-yao at the hospital, where Hsiao-tung witnesses Jen-yao crashing his motorbike and promptly calls for an ambulance. A nurse then asks Jen-yao to contact his parents to proceed with the admission formalities, as he requires overnight observation. Hsiao-tung offers to make the call, but Jen-yao gently declines, stating that they wouldn't come. Hsiao-tung receives a call from her father, pretending to be asleep, deciding to stay with Jen-yao longer. The nurse, noting Jen-yao's minor status and the illegal act of riding a motorbike, calls the police. Hsiao-tung spots the officers and rushes to the room to inform Jen-yao, only to find him gone. She locates him outside the hospital and informs him about the impending police arrival. Jen-yao and Hsiao-tung hide in a room until the police leave.
Hsiao-tung accompanies Jen-yao all the way home and into his house, refusing to leave even when he pushes her away. When Hsiao-tung inquires about his parents, Jen-yao opens up, revealing that they ran away. He explains that they didn't abandon him; rather, he is the one who no longer needs them. Jen-yao then insists that Hsiao-tung leaves.
The next morning, Hsiao-tung skips breakfast at home, serving herself an excessively large lunch and rushing to school. She encounters Jen-yao as he is being scolded by a teacher for the accident and his escape from the hospital.
During lunchtime, Hsiao-tung searches for Jen-yao in their classroom and witnesses classmates bullying him due to his poverty. She follows him to the rooftop, but he declines her lunch invitation, saying he doesn't want her pity.
The entire day, Hsiao-tung is in a foul mood due to Jen-yao's actions. In the evening, she decides to confront him at his house, stating that she treats him as a friend because they met and got to know each other, which is how people typically form friendships.
Jen-yao's heart quivered with apprehension over what others might say about her, while Hsiao-tung bravely walked with her head held high, unburdened by such worries. One day, Jen-yao offered an apology, and Hsiao-tung left her abode with a lightness in her step, her heart filled with joy. The next day, Hsiao-tung's spirits soared at school, and Yun-chen couldn't help but notice the warm smiles they exchanged as they chanced upon each other in the hallway.
In the evening, Yun-chen waited patiently for Hsiao-tung after her dance practice, the two of them strolling home hand in hand. As they discussed Hsiao-tung's fear of performing the solo dance at the upcoming school competition, with her idol as a guest of honor, Yun-chen's words of encouragement echoed with sincerity. But their tranquil moment was abruptly shattered when they encountered Yun-chen's grandmother.
Yun-chen's demeanor shifted, and in a moment of reluctance, she told her grandmother that Hsiao-tung was not her friend. These words weighed heavily on Hsiao-tung's heart, and Jen-yao noticed the change in Hsiao-tung's demeanor the next morning as they made their way to school. Yun-chen, seemingly unconcerned about Hsiao-tung's discomfort, ignored her when she dropped her off at school the following day.
During lunchtime, Yun-chen tried to strike up a conversation with Hsiao-tung, only to be met with a polite but firm refusal, as Hsiao-tung revealed she had plans with a friend. Yun-chen wanted to warn Hsiao-tung about associating with Jen-yao, but Hsiao-tung reminded her that she had no such right since they were not friends.
Instead, Hsiao-tung and Jen-yao shared a meal on the rooftop, their bond undeniable. However, a photo of them together was taken and reported to the school's discipline office, sparking an investigation into their supposed secret relationship, which was strictly forbidden.
Hsiao-tung was called to the school's military office while Jen-yao met with the school counselor. It emerged that someone had reported them for their alleged inappropriate behavior on school grounds. In the military office, Hsiao-tung was asked to sign a statement promising to cease all contact with Jen-yao, both within and outside of school, or she would forfeit her spot in the ballet dance solo. Despite the threat, Hsiao-tung refused to sign anything, steadfast in her belief that they had done nothing wrong and that Jen-yao had not coerced her in any way.
In the counselor's office, Jen-yao is pressed to confess whether he coerced Hsiao-tung. With his reputation at school weighing heavily on him, Jen-yao decides to save Hsiao-tung by claiming that she was forced into the situation.
Just as the tension reaches its peak, Yun-chen bursts into the office, having overheard her classmates gossiping about the incident where Jen-yao was reported for kissing a girl on the rooftop. Knowing that the person Jen-yao had lunch with was indeed Hsiao-tung, Yun-chen decides to take the blame and tells the counselor that she was the one with Jen-yao.
Hsiao-tung learns of Yun-chen's act of bravery from the military teacher and rushes to her classroom to see her. However, Yun-chen's grandmother has already been called to school to take her home, denying Hsiao-tung the chance to speak with her.
At home, Yun-chen's grandmother orders her to take a shower. As Yun-chen begins to undress, the grandmother bursts into the room and starts scrubbing her painfully with a brush. Yun-chen's arms bear scars, most likely from her grandmother's harsh punishments. The grandmother insults her, labeling her as ill-mannered just like her mother. In a fit of anger, Yun-chen pushes her grandmother and runs out of the house. She runs into Hsiao-tung, who had come to check on her.
