Widow's Blush - Michelle Bennington

Lady Ravenna Birchfield yearns to put her dark past behind her. Nine months after losing her husband, she wants to return to London to lead a quiet life of charity work and fencing lessons. But those plans fall apart when her old friend, Foreign Secretary Lord Hawkestone, pays a visit and doesn't leave her drawing room alive. 

Now with other politicians mysteriously falling ill, and her stepson in line to become England's next foreign secretary, Ravenna becomes the focus of the investigation. Hoping to protect her stepson, and her secrets, she does some digging of her own in a race to discover the killer before her past is exposed. 

As the investigation draws her deeper, Ravenna finds herself trapped in the charming Lord Braedon's web. He has a reputation for breaking hearts, and in spite of her attempts to keep him at arm's length, his persistence is winning her over. Surrounded by spies, lies, and an international plot, Ravenna discovers the killer is much closer than she'd ever imagined.