This is two separate stories combined into one book. While the first couple is much more mature and rough with sadistic overtones, the second couple are more sweet and lovey-dovey. There is quite a contrast and I feel like readers will definitely prefer one over the other depending on what they like. If you like one, odds are the other one will not be nearly as enjoyable, but this is just my opinion. Both are more smut than story based, but have enough plot to satisfy.