This week I discovered a lost classic.

Lionel Davidson’s Under Plum Lake is a strange and unsettling book that draws you in and keeps you there until the end.  Then it keeps you there some more, and like the book’s hero Barry, I’m not sure if that’s such a good thing.

The lysergic splurge of the cover does give you some warning that something isn’t quite right here. Certainly it looks like a typical fantasy cover from the early 80s, but there are echoes of some other, more disturbing things in the artwork – John Wyndham’s Midwich Cuckoos maybe, or worse still, Henry Darger’s Story of the Vivian Girls.

Then you begin reading. ‘I went down again last night. I go every night now.’ It’s a great opening, with echoes of Rebecca’s ‘Last night I dreamt I went to Manderley again.‘ Immediately you know your in the company of a troubled, obsessive soul, and Lionel Davidson, an acclaimed adult spy novelist, keeps this sense of mystery throughout. We quickly learn that something terrible has happened to Barry and is likely going to happen again. The narrative follows his memories from the previous summer as they return to him in dreams. But being dreams they are fractured and Barry can’t quite put the pieces back together again.

Where Davidson actually takes us, under mountains, sea and lake, is off the chart and well into Lovecraft country. Egon is a country buried many miles beneath the cliffs of Polziel in Cornwall. It simultaneously exists as our past and our future and is home to an ancient population of thrill seeking, party loving ultra scientists. It makes Narnia look like Bognor Regis on a wet Wednesday afternoon.

‘You read stories and you see films. They show you the future, and it’s creepy. It’s a terrible future with frightening people and mad-looking places. And they’ve got it wrong. I’ve been there and it’s great. It’s a future full of fun.’

Although we begin in familiar fantasy territory – the secret doorway into an alternate world – we are met by a 99 year old boy called Dido, who leads us, naked into sci-fi central. There are boats that turn into cars and then into planes, buildings shaped like pencils, trippy theme parks and power skiing.

But what really makes this place interesting is Dido and his race of white haired, green-eyed, super evolved humans, intellectual and physical giants who live and learn for 800 years. It’s the sort of place where teenage babies play the violin. Our host Dido is an overachiever even amongst the people of Egon. Super precocious and massively arrogant. He lures Barry into his world as an experiment to show off to his friends on the power slopes of Mount Julas, a guinea pig to teach dangerous new tricks.

The scientific ideas here are terrific, taking us far beyond the space operas that were popular when the book was released. The underworld inhabitants have learnt an important lesson about how to use their technology; having previously attempted to move the entire earth to a more conducive part of the galaxy, they accidentally created ‘the great mess-up’ that ultimately led to the creation of life as we know it.

But the narrowly averted disaster made them face the unsustainability of power sources like the sun and the stars. They created instead, receivers that allow them to conduct their power, and produce an internal solar system. This same ingenious logic allows them to produce meat without any need for killing animals. ‘When you ate a steak all you were eating was grass that a cow had processed. He said you didn’t have to kill the cow to get at the steak. You could make the steak the same way the cow did. You could make anything, and they did.’

Under Plum Lake is an alien abduction story. It’s also a story of a doomed friendship; Barry’s internal struggles as he comes to terms with what has happened under Plum Lake, and Dido’s emotional awakening are what make this book compelling and haunting. I won’t give away too much about the ending other than to say that Davidson does something that stays true to the emotional core, but in the bleakest possible way. Even today’s tough YA novels might shy away from such an uncompromising final message.

Next week: A Halloween Sci-Fi mash up – Space Witches!