You and Mario had finally made it to the final stage in King Koopa's castle, the whole experience was very weird however defeating King Koopa would probably give you both a break, until you get to the bridge and instead see... LUIGI!? Mario is shocked to see his brother siding with their enemy, and Luigi reveals that he was tired of staying in his shadow, the brothers will have to fight to the death, but Mario just wants to reason with his bro Luigi please, you should've told me sooner...