Machine translation

Our protagonist, Chise is a student in a magic academy.
She visits a rural area with a cave accompanied by her elder brother
(can be renamed) for her graduation examination.

"It's gonna be a piece of cake because you've already graduated and I've got good grades!"

She thinks nothing difficult would happen in the examination, but...!!

The too brother-loving little sister and the salacious sister-loving
elder brother's slightly risque adventure begins.

At the beginning of the story, there are two choices which lead to two different scenarios:
- Route 1: The little sister gets in heat and becomes lewd
- Route 2: You suppress the little sister's estrus
(Conversations and H scenes differ between the two routes)