The Twilight before Christmas by Christine Feehan
Kate Drake, a well-travelled bestselling novelist, is one of seven sisters. Seven very special sisters who happen to be witches. When she returns to the small coastal town in northern California where she grew up right before Christmas to attend her sister's wedding, she decides to settle there. She intends to open a book store in a charming, but run-down and spooky historic house. While Kate is clearing out the basement an earthquake occurs, knocking down part of the wall and revealing a burial crypt. Kate turns to the handsome carpenter who is helping her renovate the house. But Kate begins to sense that neither the carpenter nor the law nor any other worldly power can help her arrest the evil that was released from the crypt. She will have to summon all of her supernatural power - and that of her six sisters - to destroy the evil that is casting a dark shadow over her hometown.