Mistress of Sins by Hazel Hunter

Unless Miss Jennet Reed attends the All Hallow’s Eve masquerade being held at Dredthorne Hall, her family will be cursed forever.

Or so her frantic mother insists after receiving a threatening note. Jennet knows it’s utter nonsense, but to appease her mother, she agrees to attend. It’s a lavish affair and a lighthearted evening until an unexpected guest arrives.

Baron Greystone, who inexplicably deserted Jennet at their wedding altar seven years ago, has returned. Though Jennet refuses to give his astonishing story any credence, her heart does otherwise. Only when lethal visitors follow in his wake does she begin to believe him.