Yuuki Rito, a typical high school student with a knack for awkwardness, finds his world turned upside down when an alien princess, Lala, lands in his bathtub. Thanks to a mix-up, he ends up engaged to her, thrusting him into a whirlwind of intergalactic affairs, rival aliens vying for his affection, and a comedic harem scenario. The saga continues in To Love Ru Darkness, where Lala's mischievous younger sister Momo schemes to wed Rito by orchestrating his coronation as the ruler of their cosmic realm, granting him the freedom to marry multiple women.