Nagami Yuu was a high school student aiming to become a light novel author, but he always stuck failing at the preliminary screenings. Then one day his little sister Suzuka comes to him with a shocking confession--she's won first prize in the new author contest!

The most beautiful girl in school, Himuro Mai, appears before Yuu. After learning that she's actually the light novel author, Enryuu Homura, she announces her desire to study Towano Chikai's talent and begins forcing her way into his private life.

Reika proposes that Suzuka should introduce a new heroine and add more fanservice scenes. However, since she doesn't know what makes a scene fanservice, she learns about panchira (panty shots) from Yuu and tries recreating one herself?!

At Towano Chikai's signing, a beautiful woman proclaims to be a huge, huge, huge fan of his work. To Yuu's surprise, that woman is the popular voice actress Minazuki Sakura! She's also gotten so absorbed into the novels that she starts calling Yuu "Onii-chan"?!

Yuu and the others arrive at Mai's villa where the women have fun with Yuu on the beach, get him to lather them up, and cause an unexpected event in the shower room! Meanwhile, Mai also takes bold action to try and uncover Yuu's secret!

Yuu and the others help Ahegao Double Peace-sensei at a doujinshi exhibition. There they encounter the Kanzaki sisters who run a major circle. After getting caught up in the sore relationship between them and Ahegao Double Peace-sensei, Yuu gets roped into a doujinshi competition!

As the creation of their doujinshi enters its peak, Suzuka comes down with high fever. Yuu follows her requests to pick out her underwear, wipe her down, etc., but then she comes at him with an even harder request!

Towano Chikai's work is finally getting animated! The meeting with the director is just around the corner, but Sakura intrudes on their home after running away from hers. They both wind up hiding from Suzuka and spending the night together, but...

In order to prevent the novel's heroine from being revised, Yuu must perfect his love of little sister moe. Yuu and Suzuka both attend Sakura's radio program as guests, and Yuu begins flirting with Suzuka while on air as part of his training to become moe for little sisters, but...

Fading footsteps. Overlapping memories. It all started with the promise made that day. One who couldn't be honest with herself. One who constantly looked away from the truth. Will Yuu and Suzuka be able to face their true feelings?