Bundled with the 9th volume of the original novel, it is the unaired 13th episode of the TV series.

Completing every job with ruthless accuracy, Train Heartnet is an infamous assassin with no regard for human life. Donning the moniker "Black Cat" in the underground world, the elite killer works for the powerful secret organization known only as Chronos. One gloomy night, the blasé gunman stumbles upon Saya Minatsuki, an enigmatic bounty hunter, and soon develops an odd friendship with her. Influenced by Saya's positive outlook on life, Train begins to rethink his life. Deciding to abandon his role as the Black Cat, he instead opts to head down a virtuous path as an honest bounty hunter. However, Chronos—and particularly Creed Diskenth, Train's possessive underling—is not impressed with Train's sudden change of heart and vows to resort to extreme measures in order to bring back the emissary of bad luck. This assassin turned "stray cat" can only wander so far before the deafening sound of gunfire rings out. [Written by MAL Rewrite]

Zoids are beast-like fighting machines used in both everyday use such as transportation, and special use such as war. Some types of Zoids, know as Organoids, are miniature Zoids that are living organisms. These Organoids have the capability to fuse with a non-living Zoid and make it much more powerful. Van (Ban) Freiheit discovers a Zoid Organoid in an abandoned laboratory while running from two strangers piloting Zoids. Also in the laboratory, in an animated suspension tube is a strange girl. He breaks the tube open and takes her and the Organoid with him. Spotting a ruined Shield Liger Zoid outside nearby, the Organoid fuses with it and repairs the damages. Making his escape, Van names the Organoid Zeke, and decides to keep him as a friend. The girl, who says her name is Fiona, wants to find something called Zoids Eve, and so Van, Zeke, and Fiona begin their adventure. (Source: AniDB)

In her everyday life, Yuuna Yuuki is a hero. As proof, she is in her middle school's Hero Club, where she does her best to help others and bring a smile to everyone's face. But Yuuna, always up to any task, is about to become an even bigger hero. Mysterious destructive forces called Vertexes begin threatening the world she loves, and the Hero Club is called upon by a strange phone app to save it. Along with her best friend Mimori Tougou, as well as sisters Fuu and Itsuki Inubouzaki, they must transform into magical girls in order to battle the Vertexes. In between studying and putting on shows for kids, Yuuna and the Hero Club must fight for the very existence of their world and face the harsh truths behind their own powers, all the while discovering what it truly means to be a hero.