It’s Okay to Fall For a Stepsister, Right?

Mahito Utsurugi is hated by his younger sister, Yuuri. But everything changes when their parents suddenly reveal that the two are actually step-siblings—and as a result, Yuuri mysteriously loses only her memories of Mahito. After her discharge from the hospital, Mahito tries to look after her, but… she’s acting way more affectionate than before!?
Her attitude has done a complete 180—now Yuuri is closing the distance between them like it’s the most natural thing in the world, leaving Mahito confused and constantly on edge!
“I just want to make your heart race too, Onii-san.”
Yuuri’s hidden brother complex begins to spill out uncontrollably, and thus begins a sweet cohabitation life with a stepsister who’s even more affectionate than a girlfriend!