Jeanette Winterson's eighth novel starts ominously. "My mother called me Silver. I was born part precious metal part pirate." This whimsical statement is printed in large type, like those municipal artworks that spell out arbitrary words in a bold serif font, the typesetter's shortcut to profundity. "A beginning, a middle and an end is the proper way to tell a story. But I have difficulty with that method," says Silver a few pages later, apparently continuing the slide into poetic muddle. So it is a surprise and a delight to find a fine novel rising out of the opening mist.

At ten years old, Silver is orphaned. As is the way in the town of Salts, she is advertised on the parish noticeboard, and a blind old man named Pew takes her on as his apprentice. Pew is the keeper of the Cape Wrath lighthouse, a "white tower of hand-dressed stone and granite . . . 66 feet tall, and 523 feet above the sea". The lighthouse is real: like most built by the Stevenson family, it still stands today. The name comes from the Norse for "turning point", Cape Wrath being the north-westerly tip of the Scottish mainland, where the Norsemen turned to head for home. Lighthousekeeping folds the fictional and factual histories of the lighthouse cleverly together. Silver's story, a fragmented narrative ranging across Scotland, Bristol, Greece and Capri, is interwoven with the stories of the Pews, the Stevensons and the lighthouse owner's son, Babel Dark, preacher and hypocrite, passionately in love with a woman who isn't his wife.

This is northern magical realism, sparer and emptier than its Latin and Indian cousins. Winterson's novel cares little for plausibility, yet is careful to make the small things feel true. The lighthouse runs, as lighthouses should, on bacon sandwiches and Brasso and pots of Samson Full Strength. The post brings catalogues for thermal underwear. Pew pauses in his tale-telling to eat chops with tomato sauce. The Victorian half of the novel is similarly alert to the humble and specific. Babel struggles with his wife's breakfasts of tepid tea and cold toasted muffins. Visiting the Crystal Palace exhibition of 1851, he holds his blind baby up so she can feel rivets and cogs and then buys her a clockwork bear. It is this attention to detail that stops the novel from getting lost in a metaphorical sea.

The lighthouse works as an extended metaphor - an obvious idea, but obviousness is one of the satisfactions of this novel: like a good fairy tale, it fulfils expectations. When Silver moves in to her new home she finds that although the lamp flashes once every four seconds, the inside of the tower is unlit. "Darkness came with everything. It was standard." This is reflected in the character of Babel. Outwardly a pillar of society but inwardly, he fears, "not much better than an ape", he is contented only when visiting his lover, Molly, which he does for two months of each year. Travelling south to see her, he goes by the name "Mr Lux". At home, beating his wife, he is emphatically Mr Dark. It is after meeting Babel, according to Winterson, that Robert Louis Stevenson writes The Strange Case of Dr Jekyll and Mr Hyde.

Everything in Lighthousekeeping is full of enjoyable echoes. One day a ship called the McCloud sails past Cape Wrath. It is a modern boat, "turbined, sleek, computer-controlled", but it is haunted by a brig of the same name that sank 200 years earlier. On certain nights, Pew tells Silver, the old sailing boat is visible inside the new one, "hanging like gauze on the upper deck". It is similarly possible to trace the ghosts of older, bigger books afloat within the sleek frame of Lighthousekeeping. There are echoes of To the Lighthouse, of The Snow Goose, of The French Lieutenant's Woman. Their presence only adds to the pleasures of this slight but sparkling book.