The story follows the relationship between two co-workers, office worker Rena Yukuhashi and businessman Ryouhei Hachiya. Yukuhashi seems like the plainest woman at her company, but she transforms into a stunning beauty when she dresses up outside the office. Flustered upon seeing Yukuhashi transformed, Hachiya inadvertently utters what sounds like an invitation to get to know each other better — without realizing they are standing in front of a love hotel. 
 
(Source: Anime News Network) 
 
Note: The complete edition with explicit scenes was distributed web via Comic Festa Anime Zone. The censored version was broadcasted on Tokyo MX.

The usually quiet girl is moving her hips on her own... Asking me to go deeper... Letting me do whatever I want... This side of her only I know... I want to see more of it.
 
(Source: Coolmic)
 
Volume 1: Jimihen!!: Jimiko wo Kaechau Jun Isei Kouyuu (じみへんっ！！～地味子を変えちゃう純異性交遊～) 
Volume 2: Jimihen!!: Jimiko ga Torokeru Dekiai Seikou (じみへんっ！！～地味子がトロける溺愛性交～) 
Volume 3: Jimihen!!: Jimiko mo Midareru Zecchou Seikou (じみへんっ！！～地味子も乱れる絶頂性交～) 
Volume 4: Jimihen!!: Jimiko ni Himitsu no Haitoku Onsen (じみへんっ！！～地味子に秘密の背徳温泉～)
 
Notes: 
- Includes 4 extra chapters. 
- Originally serialized as a web manga under the title Jimiko wa Igai ni Erokatta (地味子は意外にエロかった). 
- Released in long-strip format and subsequently sold in traditional format.

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