Mario & Luigi: Dream Team (Mario & Luigi RPG 4: Dream Adventure in Japan and Mario & Luigi: Dream Team Bros. in Europe & Australia) is an upcoming title for the Nintendo 3DS. It is the fourth installment in the Mario & Luigi series. The game will be released in Europe on July 12th, Australia on 13th, Japan on 18th and North America on August 11th.
It is part of "The Year of Luigi" alongside Luigi's Mansion: Dark Moon and the New Super Luigi U DLC for New Super Mario Bros. U. The 2 titles and the DLC are in celebration of the 30th anniversary of Luigi's debut. As such, Luigi has a much bigger role in the game than in the previous Mario & Luigi games. A special edition of Nintendo 3DS XL with a Luigi themed print will be released in Japan as part of the event and include the digital version of Mario & Luigi: Dream Team preinstalled on the SD card.
STORY:
Mario, Luigi, Princess Peach, Toadsworth, and the Toads are invited to Pi'illo Island and travel to the island for sightseeing. While touring the island, Luigi takes a nap on a special pillow which opens a portal to a place called Dream World. This allows Antasma to pull Princess Peach into the world. It is later explained that there are two powers in the Dream World, the Dreamstone and the Darkstone, though the latter was destroyed by Antasma in order to create chunks so it is able to turn the Pi'llows species into stone. Mario and Luigi travel to rescue the princess and free the frozen Pi'llows.