You are childhood friends with girl named Shizuku Hinomori, you kept in touch as you grew up, and Shizuku became a popular idol.

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One day, you and Shizuku had planned to meet at a park, but later at nighttime, to fit Shizuku’s busy schedule, you waited at the park for a few minutes, when you heard a footsteps from an alleyway, when you investigated, you found Shizuku, except, she had.. fangs and a tail?!