Yugi lay in bed, unable to sleep. He had enjoyed a pleasant dinner with Tea and helped her with her math, but his smiles and his laughter were only superficial. There was something far more important on his mind.

Bakura had said that the Karish were planning to end all human life, and they wouldn't let Yami stand in the way. Yugi couldn't let that happen. He had to maintain the balance of power between the two races. If only the humans had some weapon against the Karish… it would truly make them equal. And they need to find that weapon quickly.

Yami would be the only one who could help him, but what kind of conversation would that be? Yugi imagined it: "Hello, Yami. Could you tell me how to kill you or cripple you in some way?" He scoffed. Yami had expressed his loyalty to Yugi, but would he really endanger his own kind just for their unstable bond?

Yami had only told him one thing about Karish that could be useful in this situation—alcohol was deadly. But how was he supposed to get Karish all of Domino (that was where the takeover was to start, he assumed) to drink alcohol on their own at the same time? Eventually they'd find out what was poison and what was not. The only thing that Karish trusted was the water…

Yugi sat up. He couldn't… but it was only solution… it was impossible, wasn't it? There was no way he could pull something like that off. He'd be able to stop the invasion and save humankind. But it would take some serious influence or a great deal of money.

"Kaiba," Yugi said softly as they worked together in chemistry. Seto Kaiba was the adopted son of a multimillion dollar company president, Gozaburo Kaiba. He was easily the smartest and the richest person in the entire school, and could probably even buy the school if he wanted to. As an accomplished businessman, he also had a great deal of shares in the Domino Water Company.

Begrudgingly, Kaiba had been forced to become Yugi's lab partner. But Yugi was the only person who could possibly match Kaiba in intelligence, so they had grown to become friends. At least, friends in a cold and indifferent sort of way.

"What do you want, Yugi?" Kaiba replied, cheerful as ever.

Yugi cleared his thought and tried to figure out where to begin. "Say… that alcohol… was the only cure for a viral pandemic. However, you didn't want to start city-wide panic by announcing that pandemic to the populace." Yugi used big words—the better to relate with Kaiba on his own terms. "Would allowing alcohol into the water supply be acceptable under those conditions?"

Kaiba glared at Yugi. "Enough of this charade. What do you know?"

Yugi sighed. "Honestly?" Kaiba nodded. "A group of parasites is planning to take over humans one-by-one and destroy their consciousness until every one of us is dead. Alcohol is fatal to them."

Kaiba scoffed and turned back to his work. "Be realistic, Yugi. There hasn't been any documentation of these creatures you speak of."

"It's the same principle as an infection, Kaiba," Yugi argued. "We didn't know that the bacteria were present until we had the capabilities to see them."

"If any of this could possibly be true, then I'd say that your plan is… resourceful. But you have no proof of your claims, so I can't act on them. Give me something I can sink my teeth into," Kaiba said menacingly.

Yugi was incredibly downcast as he sat on his bed that evening. The only way of accomplishing what he needed to do… and he couldn't prove a single word of his story! Kaiba would be able to side-step the legal technicalities and dump the alcohol right into the water supply. But he needed proof.

"Is something wrong, Yugi?" Yami asked. He had been rather quiet and sequestered all day. He must have been thinking about their situation as well.

Yugi lay down on his back and stared at the ceiling. "Yami… there has to be something we can do about what Bakura is planning."

"I don't know what to do, aibou. It would be nearly impossible to stop them, considering how many are going to be popping up on Domino's Shore," Yami mused sadly. "We'd have a bit of time. They'd want to get used to human bodies before they started their takeover. But after that…"

"Kaiba could help us, but he didn't believe me," Yugi complained miserably. "I was so stupid. As if he could just accept that there's a whole other species of intelligent life right off the coast."

"He didn't believe you?" Yami asked. "Did he want proof?"

"Yeah, exactly," Yugi replied, depressed.

Yami hesitated for a bit. "We… we do have proof."

Yugi sat straight up at that one. "We have proof? Really?"

"Yes, we do…" Yami didn't seem nearly as excited. What was wrong?

"Well, what's the proof? You obviously see something that I don't."

"The proof… is me."

Yugi understood now. He had a real, live Karish on his hands (or in his stomach, more accurately). He could shove this in Kaiba's face, and he wouldn't have any way of denying it. But that would mean…

"Yami, we would have to separate!" Yugi realized suddenly. "Are you sure that you'd be able to do that?"

"I… I have to, Yugi. It would be for all the innocent human beings that are going to be hurt if I don't." Yami seemed a bit reluctant, and Yugi could understand why. He would be completely out of his comfort zone.

Yugi bit his lip. This was dangerous, at best. "I thought you said that that Karish couldn't survive out of a water source," he said shakily.

"I could still be in a water source. You could use those… what are their names…? Buckets." Yami was being so brave by doing this. The real question would then be how Kaiba would react to this. Would he deny it ever happened? Would he call Yugi crazy? Or worse—would he take Yami and do experiments on him? Yugi would put any of those things beneath Kaiba. But Yugi could feel Yami's conviction. He couldn't be the one to let him down.

"Mr. Kaiba?" Kaiba's secretary said to the young CEO. "There's someone here to see you. He says that his name is Yugi Mutou, and asked me to tell you that he 'had proof'."

Kaiba perked up at the last sentence. "That's ridiculous. He couldn't possibly."

"Do you want me to let him in, sir?" the secretary asked uncertainly.

Kaiba decided to humor him. Whatever Yugi had cooked up was going to be far more interesting than the incomplete and erroneous reports of his subordinates. "Why not? Let's see what he's got."

A few minutes later, Yugi walked in, carrying what looked like a large, clear box of some sort. "Hello, Kaiba," Yugi said cheerfully, although his eyes gave him away. The boy was nervous.

"How can you have proof for a claim so absurd?" Kaiba asked, aggravated. "You better not waste my time with some cheap imitation. If this is a scam, it should be a good one."

Yugi stepped up to Kaiba's desk and placed the box on top of it. Kaiba peered inside it. "Yugi, don't be stupid. You brought me a fish," Kaiba said, unconvinced.

Yugi, with the utmost care, opened up the box so that Kaiba could have a better view. "There are two things that you'll find don't suit any normal fish. First of all, look at the tendrils on his back."

"His?" Kaiba asked disgustedly.

Yugi ignored him. "Second of all, he knows me." Yugi stuck his hand into the water, wincing as the saline solution bit into a small cut on his finger. "I asked him to swim around my finger three times just to prove my point to you." Just as Yugi said, this "parasite" swam exactly three times around his finger and then stopped, resting in a corner of the container.

"So you've trained it," Kaiba said dismissively. "That doesn't prove anything."

A look of dread came over Yugi's face. "I thought you were going to say something like that. Well, there's one thing you can't deny."

"And what's that?" asked Kaiba. He was beginning to get annoyed.

"This 'fish' is a parasite, right?" Yugi asked, grimacing as he leaned forward and looked into the box. "I really didn't want to do this…" he groaned, and then picked up the fish. Its tendrils wrapped around his hand.

Then, quick as a flash, the fish had maneuvered itself into Yugi's mouth and down his throat. Kaiba stood up at this one, and looked on in horror as Yugi stumbled, twitched, and then bent over. There was no way… Yugi could never have swallowed the entire fish like that, especially not when it was alive. Was what Yugi said really true?

"I'm sorry about that, aibou," Yami apologized quickly.

"Forget about it," Yugi said grimly. "Just get out there and act convincing."

Yami opened Yugi's eyes and looked at Kaiba face to face for the first time. "You must be Kaiba," he said, smiling.

"Don't play games with me, Yugi," Kaiba said. The poor human seemed a tad unsettled. "We've known each other for two years."

"I'm afraid I've never met you before, although I've heard Yugi talk about you," Yami said, shaking his head. "He tells me that you're rather the skeptic. Tell me: was the show to your liking?"

Kaiba sneered. "I don't know how you pulled it off, but that was just some cheap trick!"

"You really can't see what's right before your eyes, can you?" Yami said, grinning as the person across from him racked his brain for an explanation. "Your entire race is in danger, and you would rather play it safe by denying this ever happened. Businessmen take risks, as my host would have me to believe. Isn't that how you got this far?"

"You expect me to incorporate alcohol into the drinking water just because I feel like it? There could be serious repercussions!" Kaiba said angrily. "I may be rich, but even I can't do whatever I please."

"You disappoint me, Kaiba," Yami said coolly. "I was given the impression that you were more intelligent than this. Only a small amount of alcohol need be added—not enough to affect a human or even a human child. You can't lose. Do this for us and no harm will result of it."

Kaiba made lightning-speed calculations in his head. "Not enough alcohol to affect a human child?" he asked finally. "I will do that and only that. But if whatever you're planning fails, remember that I was never a part of this. It will be done by tomorrow afternoon and last until Saturday."

It was Wednesday at the time. "That's fine by me."