The books are tightly linked, so do not read them out of order! I suggest you start with Madison's Life Lessons - The Road to Hell prequel and then read them one after another until the end with Genesis Queen, for maximum enjoyment! :D
So Nix is in Hell now (he was tricked) and Mads is doing everything to get him out!
The story get complicated, while Nix is enjoying himself in Hell. And I mean enjoying!!!
Mads, in her effort to save Nix who is revealed to be the direct descendant of Jesus – the Ark of Heaven, get trapped and transported in Hell where her demon is awaken and she’s revealed to be one of the most powerful succubus – a Lynx!
What I love about this series is that is so complicated, but at the same time so linear. Every action gets its reaction – as smooth as that! Like a Rubik’s Cube: you more one square and everything gets garbled! Really great plotting!
I’ll not say anything more, because if I start it would be a loooonnggggg review full of spoilers, but please, please read this series!