Another read out of order, but that's not a problem with this series. While all the brothers appear in each one, they can be independent stories as well.
A wealthy uncle with a mischievous streak leaves all his money to his nephews on one condition - that they reform and marry a fallen woman before he dies (which is probably very soon). The head of the family, Jasper, the Earl of Blackwater, takes the lead and heads to the nunneries to see if any of the women there could be paid to play along. This is where Clarissa runs into him - quite literally.
Given her dress and their location, Jasper makes many assumptions, but Clarissa isn't anything like he thinks. She actually quite virtuous and on the run from a horrible horrible guardian. This storyline really added quite a bit of excitement to the story that was very nice. There is a constant threat lurking over her and she is never quite sure who she can trust. This leads to lots of lies of preservation and makes Jasper quite angry at times.
This deception carries almost to the end of the book and it's resolution was brilliant. Even though they don't quite trust each other, they find that they really enjoy each other's company and both wonder what if it would be so bad if their arrangement was permanent. This was a very exciting romance, as was book three, and I loved how the action and romance were tied together so well.