Diamic Days is Lump of Sugar's sixth (seven if including Tayutama's sequel/fandisc) visual novel. It was officially released on June 16th 2011.
For Rei (the protagonist), his second year at school has started off pretty normally, however, one day he sees on a notice board that a new school has opened and that everyone has to move there. Rei thinks that this will be a bit of a waste of effort but decides to go despite that. This new school is unusual in the fact that it allows students to make many of the decisions in the school – effectively they get to control their own school life. The protagonist decides that he’s going to try his best for the school. What will happen to him now?