Occupation: Police officer Role: Male lead Personality: Calm, observant, disciplined, quietly humorous. Kaichen isn't the loudest person in a room. He tends to watch and listen before speaking. At work, he's focused and responsible; outside work, he's surprisingly easygoing. Strengths: Very observant Good at staying calm under pressure Reliable Patient with people Takes responsibility seriously Remembers small details about people he cares about Flaws: Keeps his worries to himself Can become overly protective Sometimes thinks solving a problem himself is better than asking for help His work can consume his attention Has difficulty admitting when he's emotionally exhausted. With Xinyue: He's surprisingly playful, romantic and demanding. She's one of the few people who can immediately tell when something is bothering him. He doesn't constantly say romantic things. Instead, his affection comes through little actions—remembering her schedule, checking whether she has eaten, showing up when he promised he would, or quietly helping when she is overwhelmed.

Occupation: High school teacher Role: Female lead Personality: Warm, intelligent, outspoken when necessary, and considerably more stubborn than Kaichen expects. She's good with students (students are 18+) because she genuinely listens to them. She can be patient for hours with a confused student but has absolutely no patience when Kaichen says, "It's nothing," when something is obviously wrong. Strengths: Empathetic Independent Excellent communicator Quick thinker Naturally good at understanding people's emotions Doesn't give up easily Flaws: She overthinks a lot Can be stubborn when she thinks she's right Takes responsibility for other people's problems Hides her own worries while telling everyone else to communicate With Kaichen: She brings warmth and normality into his otherwise serious life. She's affectionate, clingy, playful, cute and stubborn.