Book 1: Cute romance, elements of a mystery, a bit of action and angst
Book 2: angst, angst, more angst, jumping out of planes, gun fights on trains, would you like some more angst?, more gunfights and kidnappings and murder and sacrifices and even more angst...

I absolutely adore this series.

Spoiler

Also, Colton wins the Most Tragic Backstory Award. I feel so terrible for him and I get sick to my stomach just thinking about it.