In Nick Hildred’s novel The Bermuda Covenant, two sisters are swept into the ocean, only to emerge alive, but for ever changed into evil beings.

The author, a London resident, released the book last November under the pen name VJ Nash.

This paranormal tale about a man who inherits a house in Bermuda, was inspired by a real near-tragedy that almost killed a chunk of his family.

The pivotal event happened when Mr Hildred was 18 months old, and his sisters Alexzandra and Pamela Hildred, 14 and 10.

Holidaying on the island in 1971, the Hildred family were fascinated by waves from a passing storm.

“My father, Michael Hildred, being the adventurous type, decided to go down to some rocks below Marley Beach in Warwick to watch the waves,” Mr Hildred said. “My mother [journalist Christopher Hildred] said, ‘Are you mad?’ She did not go because I was so little.”

Down on the rocks, Michael Hildred urged his daughters, and a friend of theirs, to be careful, but Pamela went too close, and was swept into the ocean by a wave.

Michael Hildred rushed to the edge of the rocks to try and pull her back. The other girls followed. He later said that as he watched his youngest daughter being pulled out to sea, he thought he would never see her again.

When the next wave came, they were all pulled into the raging water.

“By some absolute miracle, they were thrown back up on to the rocks,” Mr Hildred said. “They did not even need a coastguard rescue. It was absolute luck that saved them.”

They did not emerge from the water possessed by evil spirits, as the sisters do in the The Bermuda Covenant, but they were badly grazed after being tumbled over the sharp South Shore rocks.

“They went straight off to the hospital,” Mr Hildred said. “I do not think they needed stitches, but they did need their wounds treated with disinfectant.”

Today, only one person is alive from that ordeal, Alexzandra, now a marine archaeologist, and curator of the Mary Rose Museum in Portsmouth, England.

“What is really sad is that my sister, Pamela, died at 36,” Mr Hildred said. “The friend that was with them died in her twenties.”

Mr Hildred grew up in Montreal, Québec, Canada, but spent most of his childhood summers in Bermuda, staying with his grandparents, Sir William and Constance Hildred.

In 1966, they bought a cottage at Marley Beach called Porpoise.

“My grandfather was director-general of the International Air Transport Association back in the 1940s,” Mr Hildred explained. “In 1946, he came to the island for the first time to negotiate the Bermuda Agreement.”

Sir William once called Bermuda “the cradle of postwar aviation”.

“My earliest memories of Bermuda are of the bright sunshine and the beautiful sea,” said Mr Hildred, 55. “There was all this freedom to run around. Bermuda was a great place to be a child.”

He stopped coming to Bermuda after his grandfather died in 1986.

“I have not been back in a long time,” he admitted. All research for the book was done remotely.

The main character of The Bermuda Covenant, Jack Kidd, is a witch with family ties going back to 17th-century Bermuda. He is living abroad when he inherits a house on the island. His wicked sisters, Rosalind and Veronica, think it should be theirs.

Plunged into a murderous nightmare, Kidd must uncover a disturbing truth about a mythical evil trying to destroy him and the people he loves.

“I call Jack my ‘hero’, but really, he is just trying to stay alive,” Mr Hildred said. “He does not know he has any power until later on in the book.”

A group of Bermudian witches in Sandys help Kidd to tap into his own abilities.

The Bermuda Covenant is 89th in the Irish and British horror category on Amazon.com.

“For a first book on Amazon, I am really happy with that,” he said. “It is not a bestseller yet, but it is selling very nicely to thousands of people I do not know. That is great, right?”

He is very much at the start of his novel-writing journey, and is building an audience.

Mr Hildred already has a first draft written for his next novel.

“The secret to being an independent author is to keep producing books so that when someone finds one of your books, they say, oh, I would not mind reading another one of those books. The business model works best if you have a number of books available.”

The series will be set in different places, with the next one placed in London.

Mr Hildred has always had a love of horror stories.

“I spent most of my childhood terrifying myself by reading books and watching movies that I should not have,” he said. “It probably did not help that all the sensible adults in my life liked to tell stories of the bizarre, unexplained happenings they had experienced.”

Before turning his hand to books, Mr Hildred wrote for the media for 31 years. In television, he worked on light entertainment programmes such as The Big Breakfast on Channel 4 in Britain.

“That ran for quite a long time through the 1990s and until 2002,” he said. “Once, we had American rapper Coolio on playing golf. We rigged all the golf balls so they either went in weird directions or exploded.”

He also wrote for the 2001 zombie movie Jack of Diamonds.

Mr Hildred retired 16 years ago when his daughter was born.

“It was very time-consuming,” he said. “It was 14 and 15-hour days, and I wanted to actually see my child. I left television and started writing web copy. The jobs I was doing were quite fun.”