Mario & Luigi: Paper Jam is the fifth game in the Mario & Luigi series in which Luigi was cleaning Princess Peach's attic one day and accidentally knocks over a book containing the entire Paper Mario universe. This unleashes familiar Paper Mario characters and enemies into the 3D world. Bowser and Paper Bowser combine forces in an attempt to take over the Mushroom Kingdom for good. Mario, Luigi and Paper Mario must unite to stop two Bowsers!
Although the game has turn-based battles, button commands can be pressed during battle to increase your attack, defend, and counterattack. This creates the sensation of a more interactive battle system compared to other games in the role-playing genre. The addition of Paper Mario brings new tactics to the regular Mario & Luigi formula by being able to copy himself for both defensive and offensive purposes. Also new to the series are Trio moves. In battle Trio moves can be used to devastate your opponent. Out of battle they allow your party to dig under ground, grab distant objects, fly across gaps, and more.