Joanna McCrae is living a lonely life in Montauk, New York. As a kindergarten teacher, she has less opportunity to meet someone, and she has had a string of unsuccessful relationships that adds to her sadness. One day she finds a naked man lying in the surf not far from her house. She takes him home and cleans him up. She begins to become attracted to this handsome but unusual man who tells her his family is gone, that he cannot go home to Australia, and that someone may be pursuing him. He has no identity other than the name he gives her after watching the news on TV. Her sister is suspicious of Anderson, and their first meeting does not go well, however, Joanna's love for him deepens, especially when he tells her that he will never leave her like the other men did.
When a strange object that could be an alien space ship washes up on the beach, a government investigation begins. After Joanna questions the young surfer who found the object, she wants to go home and confront Anderson about it, but Joanna is followed by government agents, and must take steps to evade them. She calls and warns Anderson about the men, and by the time she comes home he is gone. Where has he gone? Was he abducted?
The story takes place in New York, London, Australia, and places out of this world. Besides the elements of mystery and science fiction, at the heart of The Stranger from the Sea is the love story of Joanna and Anderson, who may be star-crossed lovers destined to never be. Can they persevere despite all the odds that are against them?