Hello, everyone! This is my first try at mystery and also my first go writing a Detective Conan fanfic. (I told myself that I should do a fan fiction for every manga/anime that I've seen, [but then I'll end up writing over a hundred, and it's not like all of them have a category on fan fiction net…]) Plus, lately, I've been into Detective Conan more than usual. (For some reason, I've never actually been into Detective Conan. Since Detective Conan just feels like a part of my life; I've always known about it ever since I can remember.)

Also, sorry about the summary. I just didn't want to spoil anything. (I usually write good summaries. I think I've used up all of my brainpower trying to work out this story.)

Alright, to my stories first-time readers (which would highly likely be everyone…), I have bad grammar and bad vocabulary. Well, not bad. But not perfect. And my vocabulary and word dictionary is quite limited, seeing that English is my second language. I tried to be descriptive in this story (it has to be, otherwise the mystery just fails, even though it already does.), but… ;p

By the way, the title of the story was a hard case. Everything about this story was a hard case. ...My head feels like it's going to explode...

Disclaimer: I do not own Detective Conan. And I think that Aoyama Gosho-sensei (-sama!) is an utter genius.

Chapter 1 -Invitation

Conan looked suspiciously at the invitation in his hands. There was no way that the person invited could go, of course. And it wasn't if the before mentioned invited person was too keen about it either. Conan had just returned from collecting letters, cards and other things that was supposed to be sent to a certain high school detective named Kudo Shinichi from a certain Okiya Subaru. Conan stuffed the envelope into his pocket and walked up the stairs of the Mouri Detective Agency. There were other letters, but the only one that was out of the ordinary and interesting enough for him to pick it up to read was that one invitation.

The envelope was plain black. That in itself was suspicious enough. When Conan had opened the envelope, there was a slight possibility in his mind that it may be from Vermouth, like the one on Halloween Day. The invitation itself was scribed in black ink, on white paper. That was normal. This was what was written on the paper in a cursive font that Conan could easily identify; Dear Kudo Shinichi-san, the great detective of the east. We would like to invite you to our party on the upcoming 31st of May. This party is being held at xxxxxxxx. At the party, we'd like you to solve a case for us… And it goes on.

There wasn't anything much that was "suspicious", but there was a feeling that wouldn't leave Conan's mind. Or maybe he was just thinking too much, seeing as it came "in black".

Conan opened the door of the detective agency and walked in. He sweat dropped as he saw Kogoro, the same as ever, sitting at his desk. Conan went and put his school bag onto the couch and comfortably sat down. At that same moment, Ran walked into the room, 'I'm home!' she cheerfully announced. In her hands, apart from her usual school bag, was the very same envelope that Conan had been looking at earlier.

Conan looked up at Ran innocently in his "kid-mode". 'Ran-neechan. What's that?' he asked, sounding like he really had no idea.

Ran looked at it. 'Oh, this? It was in the letterbox.' She leant down so that she was closer to Conan. 'You want to know what's inside?' she asked.

Conan's face was slightly red from the space between them as he quietly replied, 'Yeah.'

Ran carefully tore open the envelope, trying not to damage it. She pulled out the paper inside, which was also identical to the one that Conan had received, and began reading it out in a clear voice. 'Dear Mouri Kogoro-san, the great detective. We would like to invite you to our party on the upcoming 31st of May. This party is being held at xxxxxxxx. At the party, we'd like you to solve a case for us. We'd gladly give you a payment of 1 million yen if you succeeds. We shall tell you the details of the case later. Please also bring friends along, as to not be too suspicious. We'd like it if you could try to remain incognito whilst at the party. From Yukimura Masahiro.'

Korogo's head had already jerked up at the "1 million yen". 'Ran!' he exclaimed. 'I'll accept this case! With one million yen, I could do oh-so-many things! ...Like this and that!' he gloated whilst laughing his idiotic laugh.

Somewhere else, Kuroba Kaito was planning Kaitou KID's next heist. The location was done, and the warning note had already been sent. He'd already found his way to sneak into the place - the family that owns the jewel will be having a party on the day, and he'd managed to get invited, by means of using connections. The big jewel that he'd be stealing this time is the "Sparkling Sapphire", a big, blue, pretty much sparkly, sapphire. He smugly smirked to himself. Of course, it's going to be another victory for Kaitou KID.

His thoughts were interrupted when Aoko slapped his desk. 'What are you looking so smug about, Kaito?' he demanded, not looking so happy.

'Oh, I'm just cheering for Katiou KID's newest success. And yet again, Nakamori-keibu's failure,' he replied, whisking out the latest newspaper that has an article on KID out of thin air. On the front page was an article on KID's latest heist that had took place last month.

'Hmp! If Aoko sees him, Aoko'll beat him to a pulp with this mop!' she declared, indicating the mop in her hand.

Kaito sweat dropped. Then he recovered. 'Kaitou KID won't be beaten by something like a mop.'

'Oh, really? I think that there's a high possibility that it might work,' Akako stated coolly, walking over with an enigmatic look on her face.

'Come to think about it, I wonder when Kaitou KID's next heist will be,' a random who'd joined the conversation wondered. Then, after saying that, the random was called by a friend, so the random left the group.

'And come to think about it, it's been a month since the last KID's heist has occurred,' Aoko said airily.

Hakuba then decided to join in. 'It has been exactly 28 days, 17 hours, 49 minutes and 21 seconds ever since the last KID heist has occurred.'

In the middle of all this, Kaito was confused. What? But I'd already sent out the warning note yesterday. Surely, the police would know by now? Or maybe they're not going to contact the police? Oh, well. An easy catch for me then. Kaito smirked to himself once more.

The Yukimura family's party on the 31st of May, huh…

Conan and company looked at the mansion with some awe. It was relatively new, and looked more like a palace than a mansion. First of all, it was huge. The walls were light brown with dark purple supporting poles, and a dark brown roof. The mansion was located on a mountain, in the middle of the forest. On the contrary, the place didn't look one bit "secluded", even though it is.

Other people that had also came along were, as followed, the usual Agasa-hakase and the Detective Boys (including Haibara). Conan was still looking at the building in front of him when a mysterious person tapped him on the shoulder. He quickly turned around at the same time as an Osakan voice began to speak. Conan gasped. 'Yo, Kudo!' Heiji cheerfully greeted him.

'Hattori!' Conan exclaimed in surprised. 'What are you doing here?'

'I could ask the same to you.'

While Kazuha was saying hello to Ran, Heiji and Conan stayed a little while away from the group for private conversation. 'Were you asked to solve the case as well, Hattori?' Conan asked, not really looking at him.

'Well, yeah. But that's strange. Why would he need two detectives for this? Only me would've already been enough,' Heiji said in an annoyed tone.

Conan's eyebrows twitched subconsciously. 'As a plus, I was also invited,' he admitted.

'Eh? You were?' Heiji wondered. Even though he wasn't that surprised.

'Yeah,' Conan replied shortly, showing him the black envelope.

Heiji looked at it for a couple of seconds then pulled it out of Conan's grasps. He pulled out the letter inside and began reading it. 'Hmm...'

The two stopped walking as they reached the main door. A butler wearing a black suit walked up to them. He looked relatively young. The butler had black hair that was combed back neatly, and brown eyes. He took a bow. 'You must be Mouri-san and Hattori-san and company. I am Nomura Junji, a butler of the Yukimura family,' he introduced himself politely. Junji looked up. 'Please, this way,' he said, then indicated a cut-off corridor to the right. Kogoro haughtily lead the way, followed by the others.

What no one saw was the look of utter hatred and abhorrence on Junji's face when the group had left for the corridor.

'Hey, Yukimura. I've really got to thank you for letting me come to this party, but…' Kaito trailed off as he stared at Aoko from the corner of his eyes. 'Sorry about Aoko. She insisted that she has to come.'

Yukimura Asashi, 17, the oldest son of the Yukimura family, who, coincidentally, is also Kaito's classmate, laughed weakly. 'It's fine, Kuroba.'

Kaito sighed. He turned around. 'And why the hell did you invite that guy, too! ?' Kaito exclaimed, pointing at Hakuba wildly with utmost dissatisfaction.

'I thought that he might be able to help us protect the Sparkling Sapphire…' Asashi replied weakly.

'And what is Akako doing here! ?' Kaito continued his complaints.

'Well, she wanted to come, so…' Asahi replied, his face red.

Behind Kaito, Akako was smirking. No one can resist my charm, Kuroba Kaito... Well, except for Kaito and Shinichi.

Kaito's eyebrows were twitching. Now that Hakuba, Akako and Aoko's here, I have to be more careful. A little more careful. It's not like they'll give me too much trouble. He thought as he smugly smirked to himself. And he definitely does not know what he's getting himself into.

I wanted to make a story that also involves Heiji, Kaitou KID and the Black Organization. I managed to fit the first two in. I'm currently trying to fit the BO in somehow. (I like my stories to be colorful.) Any ideas?

So, did you like it? Usually, I wait until I've already written at least 3 chapters before I put my stories up, but this one's different. (Who knows why.)

Please R & R, if you don't mind. Or subscribe. That would make me very happy, too. ^^