Mari & Luigi Plumber Troubles is the sixth installment to the Mario & Luigi series for the Nintendo 3DS. This time it stars Mario, Luigi, and Amelia, Mario and Luigi's teenage niece.
Bowser is at it again! He's kidnapped Princess Peach (again). But this time he's hired Wario and Waluigi to stop the Mario Bros. from rescuing the princess and will pay them big. REAL big. About a kazillion coins!!!!!!! And just when the Wario Bros have pushed the Mario Bros to a corner, help arrives in the form of Mario and Luigi's niece, Amelia. She easily beats Wario and Waluigi to a pulp and they both retreat for now. Mario and Luigi wonder why she's here. Amelia answers and says that she ran away from boarding school to follow her dream..... to be a superstar plumber just like her uncles. Mario and his brother talk it over and they both agree to let Amelia come and give her a blue custom made cap with the letter 'A'. Along with Starlow, the Mario trio starts a new adventure.
Mario- as always the superstar plumber of the Mario franchise.
Luigi- Mario younger, cowardly brother.
Amelia- Mario and Luigi's fifteen year old niece who ran away from boarding school to be plumber like her uncles. Her appearance is similar to Alma Jinnai, a character from the Jewelpet series.