Do-Type Onee-san no Yuuwaku ga Tomaranai! Chitchai Koro kara Watashinokoto ga Daisukina Toshishita Juumai no Oyome-san ni Natchaimashita! ?
どタイプお姉さんの誘惑が止まらないっ！ ちっちゃい頃から私のことがだいすきな年下従妹のお嫁さんになっちゃいました!?
A high school girl named Otose Koito falls into a coma after an accident in which she protects her younger cousin. Upon waking, she discovers that ten years have passed, and she is now in the future. Her cousin has grown into an adult and is now a woman who is drawn to her. As the cousin becomes more affectionate, Otose struggles to cope with the intensity of their new dynamic.