Scheduled for release later this month, not very much information is available for the newest Mario-centric RPG, Mario & Luigi: Superstar Saga. What is known is the unique gameplay, in which the A and B buttons each correspond to one of the brothers, and using both of them will be a core gameplay mechanic. Making proper use of both characters will help in solving puzzles, overcoming obstacles and add new elements to battle, such as timed attacks and defense (similar to Super Mario RPG).
As for the story, the game begins with the witch Geragemona stealing Princess Peach's voice. Mario and Luigi pursue the witch to the Mamelia Kingdom, joined by Bowser, who had just dropped by for his ritual princess kidnapping. This new kingdom is a whole new setting for the series, and will feature many brand new characters, as seen on our updated artwork page. In addition, we have nine new screen shots for the title.
Along with the single-player adventure, Mario & Luigi will feature a 2-4 player mode, which looks to be similar to the versions included in the four Super Mario Advance titles. Mario & Luigi: Superstar Saga is due for release in North America on November 17th and in Japan on the 21st.
(Please note character names are based on the Japanese version and are likely to be different in the English release.)