**Twelve years of separation, a fateful reunion. **
Cheng Nuan never thought that she would meet her childhood sweetheart, Zhou Hanyang, whom she had left without saying goodbye twelve years ago, opposite her home. The boy who had spent her entire childhood with her was now an elite director of a technology company. He was mature and steady, but he still remembered all her habits.
**"Cheng Xiaonuan, long time no see."**
A simple greeting tore through the dusty memories. The sudden separation, the returned letters, and the unspoken agreement all became a thorn in Cheng Nuan's heart. She originally wanted to keep a distance, but fate entangled them again - he became the technical leader of her company's project, and she was an existence he could not ignore.
**"I've seen every building you designed."**
It turns out that he never really left. He collected her college portfolio, her professional updates, and even the wishes she casually mentioned. But when Cheng Nuan finally plucked up the courage to get closer, the difficulties faced by his former boss, the appearance of Zhou Hanyang's ex-girlfriend, and the overt and covert tactics in the workplace brought the relationship between the two to a freezing point.
**"If the red light means stop and the green light means go forward, what is the yellow light?"**
**"It's waiting."**
**"I've been waiting for you for twelve years, Cheng Nuan."**
When the truth was revealed and the misunderstanding was resolved, Zhou Hanyang used their childhood agreement to light a signal light for her on the rainy night. And a year later, on the playground of the elementary school where they first met, he knelt down on one knee and completed the "ideal proposal" she had drawn in her diary.
