"Tetragun" is quite strange title for a hentai game but if you understand japanese terminology you may understand the mening of it type the text you will see through the walkthrough. If you don't understand the terminology you can play it but if it is ok for you to enjoy anime porn content without understanding the background story or dialogs. This story's idea is that you work as photographer who is specialized on erotic pictures of unexperienced models and with one of such hot girls you will be working today. Take pictures of her and get specific amount of currency for each. Those cash you can later spend at the local shop to buy some fresh accesoirs and other stuff which you can use during following photosession and that will bring you even more currency than before.