The story of Ni no Kuni revolves around thirteen-year-old Oliver, a resident of Hotroit City, whose mother, Arie, suddenly dies after rescuing him from drowning. A doll, given to Oliver by his mother, is brought to life from his tears and reveals itself to be a male fairy named Shizuku, who gives Oliver a book that allows him to use the power of magic and enter the world of "Ni no Kuni," a reality parallel to his own. In Ni no Kuni, Shizuku says, Oliver may be able to find his mother, Arie. Using the newfound power of magic, Oliver and Shizuku venture into Ni no Kuni. There, he befriends Maru, Gyro, and other alternate versions of people (and animals) he knows.
Formerly subtitled Ni no Kuni: the Another World, Level-5 announced on June 24, 2010 that this title has been replaced with two separate subtitles for the DS and PlayStation 3 versions, with the subtitle of the DS version being Ni no Kuni: Shikkoku no Madōshi and the PlayStation 3 version titled as Ni no Kuni: Wrath of the White Witch. Level-5 also revealed that both versions are being developed separately from scratch, and as such will feature different data, artwork, graphics, specifications and story developments, while only retaining the same "story axle".
Source: Wikipedia, "Ni no Kuni", available under the CC-BY-SA License.