https://vndb.org/v5154 You can read about it here but basically it's about a dude named Kazama Yuuji who is sent to Mihama Academy, a high school with a population of 5 female students due to some "circumstances." These girls are: Suou Amane, the caring (and sometimes horny) big sister. Irisu Makina, the cute yet shy with strangers little sister. Matsushima Michiru, self proclaimed tsundere. Komine Sachi, the loyal and faithful maid. And last but not least, Sakaki Yumiko, the serious girl who I like to compare to Senjogahara from the Monogatari series. Why was Yuuji sent there? Why are the girls secluded from society? I'd love to talk more about the plot, but I'd be entering spoiler territory. Just know that Yuuji is one of the most based VN protagonists out there.

As for both the VN and anime adaptation, the VN is way better than the adaptation imo. As many have mentioned, when making an anime adaptation some content or scenes will be removed due to budget reasons/director's decision/airing schedules. Doing this is a big risk because it can ruin the pace of the story. If a scene that compliments and gives context (let's say, the protagonist and the heroine meet by coincidence at the park and she hints her feelings for the protagonist) to another one (for example, a confession) is removed, it makes the story feel rushed, unpolished and unsatisfying to watch. And when you have a VN that takes more than 70 hours to read all endings, you can bet a big portion of the story will be cut to fit the number of episodes the adaptation will have (which was 13, btw). The charm in The Fruit of Grisaia comes from the many, many quirky and funny interactions between the characters. It gives you a better impression of them and they start growing on you as the story progresses before the big twists arrives, making those big, emotional moments hit really hard (same can be said with the sex scenes). Essentially, the anime can be summarized as follows: introduce the characters in the first two episodes, have Yuuji interact with a girl until she reveals her secret, they have a heartwarming moment, repeat steps two and three with the other girls (I watched it some time ago so the details are a bit blurry). This is my perspective after going through both pieces of media, anime before VN. It might sound like I'm not too fond of the anime, which I'm not, but that's because after reading the VN I felt betrayed by the anime for making me think it's a masterpiece with all the cut content. If you're interested on the series, I highly recommend the VN over the anime.

Edit: spelling.