A really good show. I rewatched it just now to give it a proper review and it was so easy to see all over again because it's so good to watch. I even cried and laughed at the same parts! No non-con or unnecessary drama. They even do a good job of showcasing different types of female side characters that we see in BL dramas: one who supports the main couple and the other that tries to get in between them. I only watch Crossing the Line and Trapped, but I'm ready to watch the rest of HIStory shows if all of the shows have such great writing with good messages about self-acceptance and embracing the goodness in your life that may come unexpectedly.
The main couple's relationship had good progression and pacing. The Professor was justified in his emotions and reactions when it seemed the younger student was still too hesitant to take what he wanted and be happy. Plus the domestic fluff from the story is downright adorable! You You as a child actor was well played and she wasn't annoying at all. Perfectly done and highly recommended.