Ao ni Hatsukoi

Rookie police officer Shiomi meets his senior officer, Chief Sano, on his first day of work. Shiomi initially feels uncomfortable around Chief Sano, who is always looking out for him, but one day he realizes that Sano is watching over him with warmth, and gradually opens up. Shiomi is drawn to the friendly and reliable Chief Sano, and his feelings grow stronger. Then, in his second year on the force, Shiomi's wish finally comes true and he becomes Sano's partner. However, his joy is short-lived when he receives the news that "Chief Sano is getting married."

(Source: Ichijinsha, translated)