Kazami Yuji, thanks to meeting the director, transfers to Mihama High School for an "unknown" reason. This school is far from ordinary. It was founded specifically for "special" students. Each of them (there are only five students besides Yuji, and all of them are girls) has their own "Tyrannosaurus" skeletons in a closet. And Yuji himself is not as simple as he seems.
P.S. About the name. It is by no means "Fruit of Grisaia." Not even close. The anime"s official logo uses a French title for no reason. Fruit is obvious, there"s no need to explain that it refers to fruit (plural, as evident from the character descriptions – each girl represents a specific fruit). Grisaia in French = Grisalle = Grizail = a style of painting predominantly in gray tones. Adding 1+1 gives the correct name.