"I dunno, guys. My big brother is pretty busy," Mokuba told the group assembled in the foyer of the office building that housed the headquarters of KaibaCorp.

"Please, Mokuba. Tell Kaiba that it's important that we talk to him right away," said Téa.

"Actually, Mokuba, maybe you can help us," said Tristan.

"Me? How?" replied Mokuba, confused.

"Mokuba, Joey found out the other day that his sister Serenity has two half-brothers. They all have the same dad," Yugi told the younger boy.

"Wow, that's pretty amazing," replied Mokuba. "But what does that have to do with me?"

"Serenity's two brothers lived for a time in the orphanage in Donkato where you guys were," Joey told Mokuba. "And we were wonderin' if you might've run into them while you were there."

"Well, it's been a long time since my big brother and I were at the orphanage," replied Mokuba. "And I don't really like talking about it that much." The smile disappeared from the boy's face.

"Please, Mokuba," begged Téa. "It's really important."

"Well, all right. I'll try to help you guys out. After all, you helped rescue me and Seto from Pegasus, so we do owe you guys one. What do you want to know?"

"Mokuba, do you know if there was anybody at the orphanage at the same time you were that were brothers like you and Kaiba were?" asked Yugi.

The younger boy shook his head. "No. Seto and I were the only brothers there. A bunch of people wanted to adopt Seto because he was a genius, but he wouldn't go anywhere unless they adopted the both of us." Mokuba gently touched the card-shaped locket that hung around his neck. "Seto's always taken care of me, ever since our parents died."

"Mokuba, do you remember much about your parents?" asked Yugi gently.

"Well, I was just a little kid when my dad died in that car crash. And I never really knew my mom…she died when I was born. But sometimes I can close my eyes and hear my dad's voice or smell his aftershave," the boy said wistfully.

"Mokuba, what was your dad's name?" Joey asked, his voice shaking.

"Dad," the boy replied simply.

"No, I don't mean that. I mean, what was his real name? Like Greg or Tommy or something like that," Joey asked once more, his heart pounding.

"Hiro," replied Mokuba.

"Oh my God." Joey suddenly looked as if he'd been punched in the stomach.

"Joey? Joey, are you okay?" Téa asked. As Joey began to sway, she quickly grabbed his arm.

"Hey, man, maybe you'd better sit down," Tristan told his pale-looking friend, seizing his other arm.

"Put your head between your knees," Yugi offered helpfully as Téa and Tristan helped Joey into a nearby chair.

"What's wrong, Joey?" Mokuba asked worriedly. "Are you sick?"

"No, no…I'm not sick," Joey insisted, although his ashen face suggested otherwise. "Mokuba, are you sure – absolutely positive – that your dad's name was Hiro?"

"Of course I am, Joey. I'd never forget my dad's name," insisted Mokuba.

"Oh God…" Joey slumped over and buried his face in his trembling hands.

"What's wrong with him?" sneered a familiar voice.

"Lay off him, Kaiba," Tristan warned the tall, unsmiling, dark-haired boy that had just stepped out of the elevator.

"If he's going to be sick, have him do it outside," continued Kaiba with a disgusted glance at the boy slumped over in the chair. "The floor was cleaned this morning, and I'd like to keep it that way."

Téa rose to Joey's defense. "Kaiba, Joey's had some upsetting news and what he doesn't need right now is any flack from you," she said angrily.

"Then I suggest you leave," Kaiba said, pointing to the front door.

"Not yet." Joey leapt up from his chair to face his rival. "Not until you and I have had words, Kaiba. Not until you know the truth."

"The truth about what?" Kaiba retorted.

Joey looked Kaiba directly in the eye. "That my sister Serenity is your sister too. Yours and Mokuba's."

Kaiba gave Joey a disbelieving look. "What are you talking about, Wheeler? Have you gone mad?"

"It's true, Kaiba," Yugi said. "Your father is Serenity's father too."

Mokuba's mouth dropped open in shock. "Is…is it true?"

"No, it's not, Mokuba," Kaiba answered his brother. "It's just a story dreamed up by Wheeler for what reason I don't know. He must be sick because he's acting delusional."

"I'm not delusional!" Joey shouted, seizing Kaiba's arm. "And I'm telling you the truth. My mom said that years ago she and your dad had an affair, and your dad is my sister Serenity's father!"

"Take your hands off me, Wheeler," Kaiba warned. "Or I'll have you thrown out."

"Why, because you're too much of a wimp to kick me out yourself?" Joey goaded. "Or you don't like hearing the truth? Is that it?"

"Don't tempt me, Wheeler," Kaiba replied with a dangerous edge in his voice. "I kicked your ass once already at Duelist Kingdom. Or did you forget…you cowering puppy?"

"That's it!" Joey lunged for Kaiba's throat, but was quickly pulled back by Tristan.

"Take it easy, man," Tristan said, trying desperately to hang onto his struggling friend. "I know Kaiba's a creep, but punching him isn't going to make this any better."

"But it'll make me feel better!" Joey replied, lunging at Kaiba once more.

"Besides, why should I believe you, Wheeler? Your mother abandoned you, so she's proven that she can't be trusted. Although…" Kaiba smiled maliciously. "Someone low enough to do that would be likely to do something like sleep with someone else's husband."

"You son of a…! I'm gonna kill you for what you just said about my mom!" Joey yanked his arm out of Tristan's grip. Yugi and Téa quickly jumped in to help Tristan hold back the flailing Joey. "Lemme go! I'm gonna beat the crap outta that piece of…"

"Get him out of here," Kaiba ordered. "I don't have time for this. Come on, Mokuba."

"You stuck-up bastard!" Joey swore as Tristan, Yugi, and Téa dragged him outside. "I'm gonna break both of your legs and stuff them down your throat and then I'm gonna…"

"Joey, take it easy," said Yugi, trying to calm his enraged friend.

"I can't believe I'm related to that sonofabitch!" Joey kicked savagely at the potted plant outside the entrance to the KaibaCorp building.

"Actually, Joey, you're not," said Téa. "Mokuba's and Kaiba's dad is Serenity's dad, not yours. They're her siblings, not yours."

"Yeah, but Serenity is my sibling too, so in some twisted way I guess that makes Kaiba my brother." Joey laughed grimly. "How's that for a sick joke?"

"Speaking of which, don't you need to get back to the hospital?" Yugi reminded his friend.

Joey glanced at his watch and gasped. "Oh no, you're right, Yug!"

Joey took off running in the opposite direction.

To be continued…