Honestly I probably could have written this as a multi-chapter story(edit: oops, I did).
Disclaimer: I don't own DCMK.
It was his third time meeting the other detective in person, but Hakuba had never really talked to the famous Kudo Shinichi about anything other than the cases they worked together to solve. The other detective was very intelligent, having seen and thought of things that even he had overlooked each time he had met with the other. It was an honor to have run into him again, he hoped that perhaps this time he could match the other's wits.
Luck was on his side as he had worn his Sherlock hat today. While it may have been embarrassing in other situations—what with Kuroba always rudely laughing at him for wearing such things. But on the scene of a crime, it gave him comfort that all cases could be solved, once you found all the facts. When he approached the Great Detective of the East to ask for details on what had been going on at the time of the murder, the other had immediately pointed his hat out, excitedly.
Hakuba knew they really should have been more concerned about the case at hand, but the way the other's eyes shone while talking about their shared hero was thoroughly distracting. He had been glad that he had someone to talk about Holmes to with. Soon the case was solved, and he had to bid the detective ado.
Hakuba encounters the detective again, purely by coincidence a few days later. They run into each other at Beika Library, which Hakuba had gone to because it had a wider selection of mystery novels than the one in Ekoda. They see each other and wave in greeting. They end up talking about their favorite mystery authors and recommending books to one another. Hakuba is thoroughly amused at Shinichi's mixed reviews on the Night Baron series. He was obviously quite a fan of those as well, to be able to talk about them in such detail. Perhaps he was embarrassed to admit that he liked his father's works that much. This time when they part, it is with a new book in their arms, and a new number in their phones.
They text each other constantly, Hakuba getting excited at every buzz of his phone, and often getting disappointed when it would be someone else. He changes Shinichi's message alert tone to a unique one so that he wouldn't get excited only to find out someone else had texted him.
Kuroba and Aoko had immediately noticed the change. Aoko asked him if he had a new girlfriend which he brushed off, telling her that it was just a friend. She didn't believe him. Kuroba teased him about it relentlessly, until he decided to peek over his shoulder at one of the texts. Hakuba hid his phone, embarrassed, but Kaito had already seen. His teasing immediately stopped, and for some reason his demeanor changed from curious to hurt. He noticed that Shinichi's text tone now always put his classmate on edge. Hakuba didn't understand why.
The next time he goes to a case that he knows Shinichi is at, he purposely wears his hat again. Not just because he is a fan of Holmes, but in the hope that he might see the way the other detective's eyes light up again. He is not disappointed. This time they talk about more than just books, and Hakuba finds to his surprise that he doesn't mind the conversation change a bit. They part with the promise of morning coffee at a nearby café. Hakuba finds himself waiting for the day with anticipation.
When they do meet for coffee, Hakuba finds some butterflies have settled quite nicely in his stomach. He thinks of it as peculiar, and he tries to deduce what the strange feeling is. Was it just that he thought so highly of the detective in front of him as a friend? Surely it couldn't be romantic interest? They were both men, and he had only ever felt attraction to girls before. When he looked up to see Shinichi's wide grin, his heart skipped a beat—and he now knew it couldn't be anything else.
Throughout the next two weeks, no matter how hard he tries to concentrate, he can only think back to Shinichi's smile. He knew all the current subject material, but he wasn't used to being distracted by things other than KID and cases during class. Shinichi sends a flirty text to him in the middle of class, making him blush. This was the first time either of them expressed interest in one another, and he found himself looking into possible meanings of it. Could he really be interested in him as well?
At lunchtime, he fiddles with his phone, rereading the text again and again. There really was no other way to interpret it, no matter how hard he tried. Had Shinichi noticed that he had been interested in him? Had he been obvious about his feelings? He didn't know. It takes him almost the whole lunch period to finally respond back, with a somewhat awkward message expressing his own interest back.
Kaito and Aoko ask him if he's okay, he responds that he's fine, to which they both give him disbelieving looks. He puts his hand on his pocket unconsciously, to find the comfort of his phone, only to find it wasn't there anymore. He looked up, Kaito had swiped it, and was looking at something on his phone. He heard Shinichi's text tone and jumped to grab it back out of his hands. Kaito's expression darkened as he grabbed his phone back. His nerves about his feelings suddenly on the backburner as Kuroba glared at him. He looked down at his phone, his messages were open. Kaito had seen it. Kaito doesn't talk to him for the rest of the week.
Hakuba and Shinichi make dinner plans, and on the day of the date, Hakuba once again finds himself wearing his Holmes hat. Shinichi sees him and comments on how he must be really fond of that hat. He was. Shinichi then says that he's really fond of it too. They eat their meal while making small talk. Pretty soon it switches from small talk to heated debates on certain deductions and cases. He finds himself complimenting Shinichi's deductive work many times throughout the night.
After their meal, Hakuba kisses Shinichi goodnight. He was incredibly nervous about it, Shinichi guided him through it, albeit nervous as well. Hakuba thoroughly enjoyed seeing the other detective flustered, as it was a somewhat rare occurrence. He asked him if he had ever kissed another guy before. Shinichi says that he'll only tell him if he promises that he won't tell anyone else. He does. Shinichi scratches his cheek awkwardly, saying that he has, once. He was at a heist, chasing KID, when KID suddenly turned around and kissed him. It was so much of a surprise to him that he stopped chasing him entirely, and Shinichi says that he thinks KID probably just did it to slow him down. Hakuba thinks otherwise, but does not voice his observations. Suddenly Kaito's actions in class made sense.
I hope you liked it!