A world where monsters and humans live together. However, monsters could also cause harm to humans. For this reason, a tool called "Metamode" was created to stun monsters without killing them, and a "Keibi-tai" (security guard) was formed by people who could use it. As time passed, "Metamode" became popular all over the world, and the "Keibi-tai" changed its name to "Cools" to protect the world. The protagonist will take an exam to join the "Cools".