The Sea King's Daughter — Barbara Michaels

Sandy Bishop arrived on the Greek Island of Thera to dive for forbidden treasure with her archaeologist father, from whom she had been separated for twenty years. She hoped it would bring them closer together, hut even now he remained strangely distant.

She felt very much alone--until she met Jim, the handsome assistant to her father's arch rival. Then frightening things began to happen on the island. There were many "accidents" and Sandy would have left had it not been for Jim. One day while she was diving, she found too late that she had swum into a trap. A trap set not by ancient spirits, but by a very flesh-and-blood enemy who wanted her out of the way--forever....