Rito Yuuki grapples with his feelings for Haruna Sairenji and Lala Satalin Deviluke, torn between the two. Adding to the love triangle, Lala's sister Momo develops feelings for Rito and orchestrates a plan to create a harem for him. Momo enrolls in Rito's school to support his love interests while introducing new contenders like the alien assassin Yami, aka Konjiki no Yami, who delays her mission for Rito's sake. Amidst this romantic chaos, Yami's sister, Kurosaki Mea, strives to reclaim Yami's past as an assassin. To LOVE-Ru Darkness picks up from its predecessor with fresh characters, challenges, and steamy encounters.