Well, without actually reading it, it's hard to say precisely. It could be that it takes the concept of a bachelor and creates all sorts of fictional scenarios around his love life, his daily experiences, or his interactions with other characters. It might also involve some elements of humor or drama based on the idea of a single man in different situations.
Since it's fanfiction, it's likely that someone has taken the idea of a 'bachelor' - which could be from a TV show, a book, or just a general concept - and created their own fictional world around it. Maybe it delves into his past, his dreams for the future, or his current struggles as a single person. It could also be a way for fans to explore different romantic or non - romantic relationships that the bachelor could be involved in, all within the realm of their imagination.