Ned Thorne has had a dream similar to one his Aunt Lal has had, of two cherubic-faced boys in old-fashioned clothes entering the bookshop run by his Uncle Adam. Returning -- not without mishap -- to the Cornish town of St Boan, young Ned has to combat with blizzards, bullies and human bugbears, the ghostly appearances of those twins being just the prelude. The key that helped him solve a mystery in the first story, In Thunder's Pocket, may prove to have a crucial part to play in The Song of Mat and Ben.

As well as the supernatural, the second novelette in the St Boan Mystery trilogy focuses on an artistic endeavour, much as the first dealt with sculpture and the third will feature poetry. This time it's music, as the title makes clear: the song is a ballad about the siblings, Matthew and Benjamin Pernel, whose demises a century before has caused ripples of resentment down the years. The questions the reader will inevitably ask are, Does Ned manage to solve the mystery? and How are things resolved? As usual, Joan Aiken doesn't disappoint in bringing things to unexpected but satisfying conclusions.

The author peppers many of her stories with snippets of verse and suggestions of music. This piece is no exception, and the illustration heading chapter 3 even illustrates the opening two bars of 'The Song of Mat and Ben', a lively jig tune in the key of D major. The rising motif bridging a perfect fourth is reminiscent of the opening of another, more famous Cornish tune, the Obby Oss song sung every May Day in the procession winding through the streets of Padstow; indeed, we are intended to recall this ceremony in the closing pages of the book, even though the action is all set during a very wintry March instead of the summer.

This being a Joan Aiken book, however straightforward a story of suspense it appears at first sight to be one can't help being alert to all kinds of fun the author is having along the way; two examples will illustrate what I mean. Set in Cornwall, the story maintains a sense of place by referencing such symbolic signposts as ancient mines, a seaside village and its local museum, and a small community where nearly everyone wants to know their neighbour's business. And that the key which Ned was given by Eden in the previous book doubtless brought to the author's mind the idea of a key to a song, which in turn provided the key to this decidedly spooky and sinister mystery. ( )