Super Mario Galaxy 2 is a platform game and the sequel to 2007's Super Mario Galaxy. Much like the first game, the story follows Mario as he pursues the Koopa King, Bowser, into outer space, where he has imprisoned Princess Peach and taken control of the universe using Power Stars and Grand Stars. Mario must travel across various galaxies to recover the Power Stars in order to travel to the center of the universe and rescue Princess Peach.