FASTENING DAYS is a oNA (web) anime that premiered in fall 2014, produced by Studio Colorido.

About the production: the story comes from an original script, there are 8 episodes of about 5 minutes and its current status is "finished".

Its main genres are adventure, with themes such as Primarily Child Cast, Superhero, Advertisement and Robots.

On AniList, FASTENING DAYS has an average score of 62%, an average score, and appears on 2,499 users' lists.

Youji and Kei, a boy and girl, live in a town in the not-so-distant future with their foster parent, Anna. But these seemingly ordinary children have a secret hidden even from their unsuspecting mother: Youji and Kei are superhero defenders of their town! With a flap of their capes, the two of them and their robot bear sidekick, Oscar, protect the citizens in their town with their handmade high-tech machinery. But from what menace? And will our little heroes be able to overcome the crisis about to threaten the town's peaceful everyday serenity? This entry contains the following: - Fastening Days 1 (1 episode) - Oct, 2013 - Fastening Days 2 (1 episode) - Aug, 2016 - Fastening Days 3 (3 episodes) - Sept, 2017 - Fastening Days 4 (3 episodes) - Dec, 2019

Official synopsis from AniList.