While exploring Wiz's magic shop with his party, Kazuma Satou finds a magical wish-granting choker and decides to try it on. Only then does Wiz tell him that the choker strangles its wearer to death in four days unless their desires are fulfilled. This wouldn't be a problem if Kazuma knew what his wish was. Fearing for Kazuma's life, Aqua, Megumin, and Lalatina "Darkness" Dustiness Ford all agree to do his bidding in order to satisfy his desires and hopefully grant his wish, no matter what he asks for...

In the winter of 1995, Mikiya Kokutou passes a young woman during a late night stroll in the snow. Clad in a striking white kimono and bearing an enigmatic gaze, Shiki Ryougi smiles at Mikiya who stares back with curiosity. Later that spring, Mikiya notices Shiki at his high school entrance ceremony, and they become acquaintances through lunchtime conversations. As Shiki begins opening up to him, Mikiya learns about her unique upbringing.

Meanwhile, a series of unprecedented murders takes place across Mifune City. Seemingly related, these murders are particularly brutal and warrant a large scale police investigation. Because of his cousin's work as a police investigator, Mikiya is given insight into the investigation. Concerned for Shiki's safety, Mikiya decides to monitor her actions, but in doing so, he stumbles upon a truly frightening discovery that changes his life forever.

[Written by MAL Rewrite]

Brought up in a conflict-ridden environment, child soldier Jonathan "Jonah" Mar hates weapons and those who deal them. But when Koko Hekmatyar, an international arms dealer, takes on Jonah as one of her bodyguards, he has little choice but to take up arms. Along with Koko's other bodyguards, composed mostly of former special-ops soldiers, Jonah is now tasked with protecting Koko and her overly idealistic goal of world peace from the countless dangers that come from her line of work. Jormungand follows Koko, Jonah, and the rest of crew as they travel the world selling weapons under the international shipping company HCLI. As Koko's work is illegal under international law, she is forced to constantly sidestep both local and international authorities while doing business with armies, private militaries, and militias. With the CIA always hot on her trail, and assassins around every corner, Jonah and the crew must guard Koko and her dream of world peace with their lives or die trying. [Written by MAL Rewrite]

Sayonara Zetsubou Sensei OVA.