The new side story is set in a.t.b.2017. A Knightmare unit made of boys and girls from Zone Eleven are thrown into a military operation with a 5% chance of survival. They must rescue an allied unit left behind on the European warfront.

Winter Days is an amazing, visually stunning collaboration of the greatest animation masters in the world joining forces to create a visual Renku, a style of poetry specific to Japan whereby composers write a poem as a group, each poet creating a different verse. Winter Days is taken from the famous Japanese poet Basho's Seven Poetry Collection, the paradigm of the sho-fu style of haiku. Led by Kihachiro Kawamoto, Japan's greatest puppet animator, thirty-five animators from Japan, China, Belgium, Czech Republic, England, Netherlands, Canada, and Russia worked tirelessly to realize Winter Days, a thirty-six part Renku opening with delicious animation seamlessly flowing from one verse to the next before taking on the form of a documentary, illustrating behind the scenes interviews with the creators. Winter Days is a visual feast for animation and poetry lovers and those who embrace alternative and innovative approaches to the Renku art form.

After intense battles, defeating Sendo, Makunouchi Ippo finally grasped the place as the Japanese Feather-Weight Champion. And so, Ippo changes from a "Challenger" to a "Champion", and the opponent of his first defence match is decided. The name of the challenger was Sanada Ikki. A fierce opponent who, aiming for a Dual Class Conquest, returned the title of Junior- Feather Class.Sanada has a different face as a Current Medical University Student, which enables the intimate understanding of the human body, of where a punch should land to deprive stamina and to down the opponent with consistent damage. Furthermore, he coolly analyses his condition from a medical perspective, based on his amount of perspiration, breathing rate and heart rate, and is thus a boxer with one of the most intelligent tactics. On the other hand, Ippo, in front of his first defence match, not only is nervous but suffers progressively from fear and anxiety as he hears more about his opponent. Furthermore, Sanada Ikki's trainer was Hama Dankichi, the rival of Chairman Kamogawa when he was still active in the ring. Dankichi's special move in the days when he still fought, "Hien" ("Flying Swallow"), has been passed down to Ikki.Encouraged by the predecessors of the gym Ippo belongs to, Takamura and Kimura, his past opponent and his mother, watched upon by Kumi who he secretly has feelings towards, the date of the first defence match draws closer. Ippo versus Sanada, and the settling of the scores of the coaches, Chairman Kamogawa and Hama Dankichi, each of their thoughts crosses over, and now, the day of the decisive match arrives!Can Ippo dodge the "Hien" and find victory?

The main character of the story is Haru. Haru is a clueless, ordinary 17 year-old girl. She has no special abilities and neither is she an extraordinary beauty. When faced with reality, she is unable to make decisions for herself, thus often swaying to others' opinions to avoid challenge. One day, Haru saved the life of a cat without consideration of her own safety. The cat turned out to be the Cat Prince from the Kingdom of Cats, however as a result, Haru is trapped in the world of cats. Can Baron and Muta rescue Haru who has wandered in the world of cats?