The short story that that novelist talked about in the last afterword?

I'm not sure if the novel has already been translated but the drama CD version had already been translated: https://koekara.wordpress.com/category/drama-cds-%E2%98%86-%E3%83%89%E3%83%A9%E3%83%9E/decoy-series/

Volumes 1, 2, 3 available in print from June (akadot.com or Amazon.) Unfortunately, volume 4 is sold out in print but you can get it as an ebook.

Thank you SO much anonymous sama ε=ε=(ノ≧∇≦)ノ