From MangaHelpers:

Anime enthusiast Sakuno Kaho attends a comic convention and is taken aback by a cosplay girl named Nonomi. Her outfit is extremely well crafted, looks identical to the original character and she looks beautiful in Kaho’s eyes. That inspires Kaho to start pursuing cosplay too. Several months later, Kato Konomi, a teacher’s assistant, comes to Kaho’s high school. Although Ms. Kato doesn’t realize it at first, Kaho instantly makes the connection between her and Nonomi. Ms. Kato explains that Nonomi is her alias when she does events and that she has been keeping it a secret from everyone since wearing skimpy clothes will affect her position as a teacher. In return for keeping her secret, Kaho learns the techniques of creating a high quality cosplay outfit from her teacher. [vyc]