"The game's opening sequence shows TwinBee and WinBee patrolling the skies of Donburi Island when they suddenly receive a distress signal from a young girl named Madoka. Madoka reveals that she is the granddaughter of Dr. Mardock, who was once a benevolent scientist until a bump in the head turned him insane. Dr. Mardock now seeks to conquer the world with an army of Acorn Men and only TwinBee and WinBee can stop him." Source: Wikipedia, "Pop'n_TwinBee," available under the CC-BY-SA License.