One day while walking home from school, he finds that someone has messed with his trash. His trash has been left behind because the different types of trash were mixed up. The perpetrator kept mixing up only Souya trash everyday, so one day Souya decides to lie and wait to catch this annoying criminal. That day, he finds that the perpetrator was actually the recently transferred classmate, Tokisaka Koyomi, and she reveals that she has come from the future to stop all environmentally friendly activity. Now, Souya and Tokisaka will have to live together and destroy the environment so that Tokisaka can go back to the future. [DrCoke]

In fifteenth century Rome, witches have declared war against humanity. A young man named Nikola, whose parents were cruelly murdered by a witch before his eyes, discovers that he is now the key to winning the war. Using sorcery skills acquired through years of careful study, Nikola must revive twelve witches known as the “First Witches” who will become his allies and weapons to defeat the enemy. But there is one small hitch: in order to revive the witches from their eternal slumber, Nikola must form a marriage contract with each one. Just how many witches can Nikola marry in order to save the world?

This story takes place during the civil war in Japan. There is a mysterious boy with a short horn on his forehead. His life turns upside down after he saves a wanted female ninja, who then tells him that she's his servant and he is an emperor!

Soon a few more girls appear in his life and the adventure begins. What will happen to him and what kind of weird and wonderful stories lie in front of the small group is for you to find out.