It's the same plotline as in the Fifty Shades. However, Gideon is somewhat a softer version of Christian and Eva's a more confident, experienced and broken/damaged version of Ana.
The lovers are both emotionally damaged (and physically, I guess, because while readers get an insight into Eva's past, one doesn't know exactly what happened to Gideon in his past, but I bet one'll find out in the sequel). While reading, I began to think that maybe two people with such emotional baggage cannot have a normal and healthy relationship (well, one couldn't claim that this relationship is exactly normal and healthy, although it could be worse), but they somehow always find their way back to each other and find strenght in one another.
I really liked Cary until the very end, but I guess I can understand why he violated their (Cary's and Eva's) apartment in such a manner. I kind of feel bad for him.. I hope Eva will help him get back on his track.
Anyway, I think you'd like this one, if you liked Mr. Christian Grey's and Ms. Anna Steele's story, although, Eva and Gideon aren't that into any toys like Christian was and there aren't any punishments involved in this book (as far as I remember). It's more of an emotionaly story spiced up with great moments in bed/on a couch (and various times in a limo).