Author's Notes: Here I am, this time with another one-shot, but a different pairing! Yeah, not everybody knows that Seto/Mokuba is my second favourite pairing after Atemu/Yuugi. I just love writing fanfics about these two brothers, may it be just pure brotherly love or more.

Warning!: Before you read, you should know that this fanfic contains incest, even though it's one-sided. Don't like, don't read. I won't accept flames of any kind. You've been warned.

The title of this fanfic is the same as episode 18 of Gossip Girl (season 1). I thought it fitted the theme of this one-shot.

I'm pretty happy with how this came out. I hope you like it, too! Feedback is loved. Enjoy! :D

Disclaimer: I don't own Yu-Gi-Oh!; it belongs to Kazuki Takahashi.

Much 'I Do' About Nothing

If there was one person in the whole world that had been close to Mokuba since God-knows-when, it was none other than Seto.

It was pretty obvious, really. Seto had always been there for Mokuba—even before Mokuba was actually born. When their father died, Seto was there to comfort Mokuba and to tell him everything was going to be alright. When they got into that orphanage, Seto held Mokuba's hand to keep him close. When Mokuba asked whether they would stay together or not, Seto promised nothing could tear them apart.

Their brotherhood was great. You couldn't quite find a lovely relationship between two brothers like Seto and Mokuba anywhere else. It was simply perfect, what they had.

Which could be one of the reasons why suddenly Seto had been developing those strange feelings for his brother—those feelings a brother shouldn't feel. As time passed, Seto noticed he loved Mokuba far more than he should; somewhere between Mokuba's sixteenth birthday and his twenty-third, Seto had begun to think of his brother as more of a brother; and he had started loving him in the most and also worst not-brotherly way possible.

However, unlike many human beings, Seto had power over his emotions. He had never, ever shown his twisted feelings in front of Mokuba and he'd promised himself their relationship would stay the same, no matter what. He had always protected Mokuba from anything that could hurt him, and now it was time to protect his little brother from the worst thing of them all—Seto himself.

Seto became a self-absorbed workaholic. He figured the less time he spent with Mokuba, the better. He made sure, however, to spend some time with his brother once in a while. Mokuba was a smart boy (he was Seto's brother, after all) and he surely would find Seto's behavior a little strange; he'd figure his nii-sama was avoiding him, sooner or later.

He didn't, though.

Probably because he was busy falling in love.

Seto hadn't even realized it at first. Now it was Mokuba that was spending less and less time with him. The Kaiba Corp. CEO suspected something was going on, but he couldn't quite put his finger on it.

When Mokuba came out of the closet and announced that, not only he had a girlfriend, but that he was engaged as well—only then Seto opened his eyes and he felt like the world had just crashed on him, quite literally.

However, he did his congratulations and said he was happy for Mokuba. His little brother was so relieved Seto wasn't against him getting married—if only he knew the truth.

The preparations for the wedding started shortly after. Seto helped, too, and offered to be Mokuba's best man. He thought getting everything set for the wedding would get him used to the fact that Mokuba was moving on and going to live a life of his own, which might not always include Seto.

Seto knew the mansion would feel damn empty when Mokuba wasn't around. He didn't have anyone else beside his brother that could keep him company. He felt so stupid, all of a sudden. He had wasted time trying not to be with Mokuba, and now—now he thought the time he hadn't been with Mokuba was actually the only time he'd wasted.

At the wedding, Mokuba confessed that he was nervous, while Seto was fixing his brother's tie.

Seto figured it was now or never.

Funny, isn't it? Of all the times he could have said it, he'd decided to do it on his brother's wedding, nonetheless.

He whispered those three words—the same three words that could change everything—and, at the same time, couldn't.

Mokuba smiled and said those three words back.

Only difference was, his was a completely brotherly love. He should have figured. Mokuba had always been far too naïve for his own good.

Seto understood everything in that exact moment. It hurt, yes; but at least now he was sure nothing would have changed, not even if he'd said those words before. It was sort of comforting—and yet it wasn't.

At the altar, his brother looked happier than he'd ever been before in his life.

"If anyone here knows why these two people should not be joined in holy matrimony, speak now or forever hold your peace."

Right there, right then—Seto did the most unforgivable mistake of all.

A mistake he would regret doing for the rest of his life.

He kept quiet.