The Heiress Effect (The Brothers Sinister Book 2)

Miss Jane Fairfield can't do anything right. When she's in company, she always says the wrong thing--and rather too much of it. No matter how costly they are, her gowns always seem to fall on the unfortunate side of fashion. Even her immense dowry can't save her from being an object of derision.

And that's precisely what she wants. She'll do anything, even risk humiliation, if it means she can stay unmarried and keep her sister safe.

Mr. Oliver Marshall has to do everything right. He's the bastard son of a duke, raised in humble circumstances--and he intends to give voice and power to the common people. If he makes one false step, he'll never get the chance to accomplish anything. He doesn't need to come to the rescue of the wrong woman. He certainly doesn't need to fall in love with her. But there's something about Jane he can't resist...even if it means the ruin of them both.

The books in the Brothers Sinister series: 
½. The Governess Affair (prequel novella)
1. The Duchess War 
1½. A Kiss for Midwinter (a companion novella to The Duchess War) 
2. The Heiress Effect 
3. The Countess Conspiracy 
4. The Suffragette Scandal
4½. Talk Sweetly to Me