Sorry this took so long, mysteries aren't easy to write. I promise the rest of the mystery will be done soon, I have the next few chapters mostly done except for the rewriting. And if anyone was confused about why Kid picked the name Arthur, well he was talking with Shinichi about why he was called Conan and he said he was thinking of the author of Sherlock Holmes, Sir Arthur Conan Doyle. So when Ran surprised him that was the first name he thought of. As always, all reviews are appreciated, especially constructive criticism.

"Here, let me carry that for you Arthur." Said Ran as they walked out of Agasa's house.
"Thanks!" He said cheerfully as he handed her his bag. Conan rolled his eyes at Kid's 'cute' act, 'He's a little too good at that' thought Conan, out loud he asked
"Ran-neechan, why are we hurrying?"
"Dad's working on a new case on an island. The client sent a private yacht to take us to the island but we need to be at the dock soon."
"What kind of case?"
"I'm not sure Conan, something about the man's nephew is accused of murder. I already packed your suitcase, but you might want to bring a book or game. We may be there a while."
It didn't take them very long to get to the Mouri Detective Agency and once there Ran gave Arthur a quick tour while Conan finished packing. When Kogoro arrived he was not exactly pleased to discover he had a new 'houseguest' but he quit complaining after Ran punched a lamppost. This display of irritation also silenced Arthur who except for a muttered comment about mops hardly said a word until they were on the boat. This was fine with Conan who happily chattered with Ran sounding as if he really was her little brother.

Once on the yacht Conan and Arthur went in search of some privacy so they could talk.
"Thanks to your stroke of genius back there, we need to work together to keep our secrets. Why did you say you were my brother anyways?"
"I didn't exactly have time to think. It's not like I could say "Sorry I don't know who I am yet, could you ask me tomorrow?"
"No, but..."
"Look Kudo, I know you're irritated about this and I'm not thrilled with pretending to be your brother either but if we work together this might be an advantage for us."
"How is this going to be an advantage?"
"People pay attention to the obvious, so if you give them an unusual feature to focus on they don't remember the other details as clearly. Twins are unusual so people will remember that before they think of us as individuals. What I'm trying to say is we'll be 'the twin boys' to most people and they won't look farther than that."
"I see, the Black Organization won't be looking for a pair of twins so they're more likely to overlook us."
"Right!"
Conan glared at him for a moment before saying, "I may not like it but you're right. Now if only you can be as big an annoyance to the Black Organization as you have been to everyone else."
"Look who's talking."
"So what's bothering you?" Asked Conan as he leaned on the rail.
"Does she do that often?" Asked Arthur as he stared out at the water.
"Do what?"
"Does Ran-san often dent steel with her bare hands?"
"Only when she's mad, or sometimes to make a point." Said Conan calmly.
Arthur groaned as he flopped down to sit on the deck near Conan's feet. "I'm dead if she ever finds out who I am."
"What do you mean?"
"Do you remember when I took her clothes and disguised myself as her?"
Conan's smirk looked odd on his childish face "Well if you behave I'll try to slow her down to give you a head start when you run for your life."
"Ha ha, very funny." Arthur was sprawled on the deck with his head tilted back to look at Conan.
"You should just tell her what happened to you, then we could sit back and watch as the men in black coats run in fear." He laughed as Conan glared at him "Just kidding! You need to lighten up, it won't help your disguise if you develop ulcers!" Now he was doing a handstand, his feet waving in the air.
"What are you doing?"
"Since I shrunk I'm not as strong or agile as I used to be. So I'm practicing and relearning the skills my mind remembers but my body doesn't." He bent over backwards and balanced on his hands and feet for a moment before collapsing on his back with a thump. "Besides, I don't like to sit still for very long. I'm going to see if I can get something to eat, you wanna come?"
"What did I do to deserve this?" wondered Conan as he watched the small boy with the mind of an internationally wanted criminal run off before he could answer.

Late that evening they arrived at the island where they were met by a tall, grey haired man wearing a dark suit.
"Are you detective Mouri?" He asked.
"Yes."
"Good, I am Ito, Nakajima-sama is waiting for you at the house. Please follow me." They picked up their bags and followed him to the car. It was a short drive to the edge of the small town and as they turned down a long driveway lined with lush gardens Ran commented on the huge trees that framed the entrance of the house.
"Yes, those are two of the largest black walnut trees in country. Nakajima- sama takes great pride in his gardens; perhaps you could have a tour tomorrow while your father investigates. The roses and the peonies are quite lovely." The inside of the house was furnished in a beautiful blend of western and traditional styles much like the gardens were. Nakajima Masaru was a short and stocky man who was wearing traditional clothing and had a worried expression on his face.
"Detective Kogoro? I'm Nakajima Masaru."
Kogoro bowed and said "I'd like to know why I was hired, you were rather vague when we spoke on the phone."
"I'm sorry, I'm not entirely sure where to begin. I suppose it started when I discovered that someone was stealing from my company and all the evidence pointed to someone close to me. Then a few days ago my son had several friends here for the weekend and he mentioned he needed to talk to my nephew, he never came back. The next day my nephew came in the house claiming he fell asleep in the garden but the housekeeper found his coat and a knife stained with blood and hidden in a storage room. The police also found a note from my son asking my nephew to meet him to talk about the thefts or he would tell me everything. My nephew was arrested for the murder of my son but I can't believe he did it; I raised him as if he was my younger son. I want you to find out what really happened, or at least find my sons body."