Taken from this weeks Famitsu magazine:

Mark and Chelsea, two characters from Harvest Moon: Island of Happiness, will return as playable characters. The new game takes place in Sunflower Islands, where you make new friends with villagers as wild animals help in the everyday tasks of being a farmer. Finding special stones allows you to uncover other islands for new areas to explore, and you can trade items and voice chat with friends over Wi-Fi.