An experimental drug that is supposed to reduce aggression has the opposite effect on a baboon that is being experimented on by a group of medical students and their professor. While they are playing a fantasy role-playing game in their research facility, the baboon escapes and begins hunting them down.。「ずっと前から好きでした。」附DVD「告白予行練習 ショートストーリー」(「告白予行練習」、「初恋の絵本」、「ヤキモチの答え」オリジナルアニメーション・デジタルコミック(フルボイス)。)。