Of note is the fact that Tracks of Light will feature a multiplayer mode, the first in the series to do so: up to four players can take on a mission together. Also, much like previous Ranger games, Tracks of Light will allow a special event Pokemon to be transferred to Diamond, Pearl, Platinum, HeartGold, or SoulSilver - a Deoxys.
All that is known about the plot so far is that the main character, a Ranger, travels the region with their buddy, a Pichu who can, unusually enough, play the ukulele. The Ranger faces the Pokemon Nappers over the course of the game, though what the Nappers actually do is as of yet unclear.
A release date for any regions outside of Japan has not been set.
From Bulbanews