I'm not sure specifically as there could be many stories with this name. It might be about the days in between significant events, like the days in between holidays or important life moments.
It's not based on a true story. The plot and characters of Mr Inbetween are the result of the writer's imagination and creative process. Although it might draw inspiration from real-life situations to some extent, it's not a direct account of actual events.
One key element is the realistic portrayal of the criminal world. Since it's based on a true story, it likely shows the gritty details, power dynamics, and the unwritten rules that exist in that world.
The themes are a blend. It includes elements of self - discovery like in young adult fiction, but also more complex and sometimes darker themes like in adult fiction. Such as dealing with career choices along with relationship problems that are more nuanced than just high - school romances.