Becoming the significant other of an alien Princess has been hard enough on Rito Yuki, but just as he's starting to cope with life with Lala, their domestic "bliss" is torn asunder when not one but TWO more princesses are dropped into the mix! Needless to say, having Lala's sisters, Nana and Momo, transfer to Earth is a recipe for disaster, especially after Momo decides that the way to horn in on Rito's relationship with Lala is to bring in even more girls! And, of course, this is the point when galactic scourge Yami, the Golden Darkness, decides to pop by with an army of possessed high school students! Now it's no longer a question of whether Rito will last to the end of the week, but whether Earth itself will survive the ultimate romantic cataclysm in TO LOVE RU - DARKNESS!