A child, with learning disabilities, runs away from other children who are teasing him because of the warts on his hands. He takes refuge near a waterfall, hears a noise, looks up and sees, silhouetted against the bright sun, the figure of a beautiful woman in green, with long blonde hair.

The figure tells him to place his hands under the water and repeat that he believed he could be healed. That next morning, when he awoke, his hands were healed – all the warts had fallen off in the bed over night and, before long, the story has swept across the island. A guest at the local inn, who suffers from asthma, hears the story, and bathes her face in the water…. and stops having asthma attacks. A newspaper reporter who happens to be present, on vacation, when she shares the good news publishes a story in a national newspaper.

And suddenly the islanders are making money hand over fist. Sick and injured people make pilgrimages to the island. The owner of the island, Fanny Winterbottom, widow of a rich grocery store magnate, wants to believe and pours money into repositioning the waterfall as a new Lourdes.

Soon the woman who was cured of asthma moves to the island, opens a shop featuring tiny statues of the “green lady” and other souvenirs. The inn expands. The home of the boy who started the whole thing becomes a tourist attraction. The local doctor’s nursing home expands. The mayor and the town counsel are excited. Everyone is excited.

And then Fanny dies and her sister, an 87-year old woman who had moved to France as a young woman, and led a squad in the resistance during WWII, and who lives in London now, tutoring diplomats in spoken French inherits. The sister, Miss Pride, had a good friend who gave up conventional medicine when they were diagnosed with a fatal illness and put their trust in faith healing. And Miss Pride’s first move is to visit the island and shut down the exploitation of the spring and the boy. Since Miss Pride now owns the island and can evict anyone who opposes her, this makes the island residents understandably concerned.

And then, before she leaves London for the island, she begins receiving anonymous death threats in the mail.

So she calls one of her former students, Sir Roderick Alleyn, now a Scotland Yard Detective, and asks for his advice. He tells her to stay home, to let her lawyers deal with it, and she declines. She’s never backed down from a fight and she’s not going to start now. Alleyn has no choice but to accept her decision but secretly gives the local police chief a heads-up and asks him to keep an eye on her.

When Miss Pride arrives at the island, she makes her position clear and faces the opposition. Someone throws a handful of stones at her, injuring her. This makes her more determined than ever to shut things down. She visits the Ye Olde Gifte Shoppe and confronts the proprietor who is so upset by her demands to cease and desist that her asthma returns. Then Miss Pride finds another death threat in her room, while she is on the phone with Roderick Alleyn who has called to inquire about her injury and plead with her to return to London. Again she refuses.

The next day there is a pageant at the waterfall to celebrate the anniversary of the onset of the miracle cures. A choir sings. The boy recites some doggerel poetry. The gift shop assistant dresses up as the lady in green and, carrying a borrowed necklace that sparkles, recreates the day that the boy saw the green lady. It’s laughable and people in the audience who have a sense of humor, do laugh.

And then the skies open up. Thunder, lightening, wind – everyone runs for shelter. Inspector Alleyn is there to escort Miss Pride to her room at the inn and he secures a commitment from her to stay in her room the rest of the night, to have breakfast in her room, and to depart the next morning for a hotel nearby on the mainland.

The next morning, however, not only is the storm worse, but they find a dead body in the pool beneath the waterfall. A woman in black, carrying a black umbrella – and for a moment everyone thinks it is Miss Pride. But it’s not – its the gift shop proprietor.

Who killed her and why? And why does Alleyn keep asking who was the original green lady?

This is one of the better Inspector Alleyn mysteries. He doesn’t come across as snobby and stiff as he does in other books; his team is presented as professionals – and even when Inspector Fox dares to speak record player French to Miss Pride, he doesn’t come across as the old school copper in his great boots. This is also a book where Marsh introduces a New Zealander, Jenny, who is teaching school on the island and falls in love with the adult son of the innkeeper.

Marsh herself grew up in New Zealand before relocating to England as an adult. From time to time, Alleyn goes to New Zealand on assignment. And every now and again, Marsh places a Kiwi fresh off the boat in England. You might think that, perhaps, Marsh would use these characters from her home country to look England from an outside perspective, to say something about England that English characters couldn’t say about themselves.

But she doesn’t.

You might assume that perhaps she wanted to say something about people from New Zealand and how they are different from the English.

She doesn’t do that either.

And that’s fine. The world is made up of a diversity of people and, when you include a character who contributes to that diversity, you don’t have to make them representative of anything in particular.

If you like Golden Age mysteries, with fun characters, and a really clever murderer, give this one a try.