Kaiba said " No I will not give that card to yugi, Mokuba" Kaiba had three guards to take Mokuba kaiba to his room and he was grounded for a week. Kaiba went to the Duel tower to see yugi lose to yami Marik . Mokuba was watching the duel from his room and He knew yugi and yami could not win this duel. Mokuba go out of his troom to get a random deck and dueldisk while running from the guards. He reached the top of the Dueling tower. He was too late. Yami Marik won . He saw the tears of Joey and all of yugi's friends. Yami Marik and kaiba was happy. Mokuba's eyes came in rage. He ran and punched yami Marik in the stomatch with a hard force. "someone punched Yami Marik. Do it again" Joey said. " who punched me?" Yami Marik said. "It was me psychopath" Mokuba said. Everyone was shocked. Kaiba knew He was gonna get beat up so he left without anyone seeing him to talk with the guards.
Yami Marik said" It is time for a shadow game Mokuba"! Téa Gardner and Everyone who was watching said " Oh no Mokuba!". Mokuba then said " This is the end of you!". Yami Marik said " That is funny." Mokuba toss his jacket and his card neklace make sure they would not be damaged. Then Yami Marik starts the shadow game and both of them said "Duel!".
Yami Marik : 4000 lp
Mokuba : 4000 lp
Yami Marik: I play the spell, Ra's call. It special summon the winged dragon of ra in attack mode from my deck and it's attack become 100,000 and you take 3800 points of damage.
Mokuba : oh no I got ra burns ! I will win! (200 lp)
Yami Marik: Then I gain lifepoints equal to Ra's attack points (104,000 lp). Thanks to my spell, My ra monster can't die! Due to this spell, I must discard my whole hand and I can't draw for my next 10 turns. I will end my turn now.
Everyone watching the duel: Yami Marik is unstoppable
Mokuba : I draw! This is for yugi , yami and everyone who you hurt. I set 1 card. I play Reversal Quiz! I send other cards I have in my hand or my graveyard to the graveyard. I guess spell card is on the top of my deck. If I am right, we switch life points!
Yami Marik: what! No way!
Mokuba: I am right! we switch lifepoints! (104,000 lp)
Yami Marik: oh no! (200 lp)
Mokuba: Then the effect of Fuhma Shuriken in my graveyard. Since It was sent to the graveyard, you lose 700 lp meaning I win!
Yami Marik: I lost! (0 lp)
Yami Marik was sent to the shadow realm. The real Marik,yami , yugi and every one who was tortured by Yami Marik. Yami and Yugi asked "who defeated yami Marik?". " It was Mokuba". Joey said. Mokuba got up grab his coat and card necklace and still injured from the shadow duel. Serenity, Mai,Bakura and odion came to the top of the Duel tower. They said "thank you Mokuba." Ishizu Ishtar told everyone why Mokuba dueled Yami Marik. Everyone was shocked and Mad at kaiba but gained respect from Mokuba. Kaiba came back to the top of Duel tower and saw yami and yugi and freaked out. Mokuba's two legs were broken due to the shadow duel. Everyone expect kaiba saw the pain Mokuba was in. Everyone was keeping their cool expect Serenity Wheeler .Kaiba said " You disobeyed me Mokuba .". Kaiba punched Mokuba in the face. Mokuba's half of his face was bloody. Kaiba went for a 2nd punch but was kicked in the stomatch by Serenity Wheeler. Serenity wheeler said "you are a monster! Mokuba came to defeat Yami Marik to save my brother's friends and try to correct the mistakes you did because he cared about you and you thank him by punching him for disobeying you. Seto kaiba is a monster." Serenity Wheeler and Téa Gardner picked up Mokuba to take him to doctor to get better.
Mokuba recovered in 2 days. Kaiba was required to take a 4 week anger management cours. For 2 Months Téa Gardner had custody of Mokuba kaiba . After the 2 Months,Mokuba came back to seto. However It would take kaiba a Mokuba a while to build back the brother relationship.