A visit to the Jamaica Inn is full of mystery and surprise - not only for orphaned Mary Yellan who goes there to live with her estranged aunt and scary uncle but for the audience of this Salisbury Playhouse production as well.

Mary, enthusiastically played by Kathryn Sumner, at once realises there is something not quite right about an inn where nobody ever stays.

Poor Aunt Patience is in thrall to her brutish husband, Joss, and begs Mary to ask no questions about how the couple make their living.

Of course, the feisty heroine takes no notice and, by spying on his activities, she soon puts two and two together on the smuggling front.

However, she gets her biggest surprise one night when Joss is in his cups and confesses the true extent of his villainy.

It takes a few more twists of the plot before she can extricate herself from the Inn and all it stands for.

Surprises for the audience begin with the realisation the play is a musical. Well, not exactly but there are musical interludes liberally sprinkled throughout.

As a device to move the plot along it works quite well, although the words are not always clear enough to carry key information.

Later, we are treated to whippings and nudity (yes, really) and what appear to be wire-coathanger gulls, sheep, horses and chickens animated (briefly, thank goodness) by the actors.

As for mystery, while Mary is vexed by the question of what is locked in the old lumber room at the end of the passage, the audience are probably still trying to fathom out who the woman at her elbow is, given that she is ignored by everyone on set except Mary. (A tip: In the programme she is unhelpfully listed as "Woman". But it is quite certain by the end she is Mary's dead mother.)

Full marks must go to the company for effort with this tricky adaptation. The play has something for everyone - comedy, tragedy, music - but you can't help thinking less might have been more. What could have been dark and menacing is occasionally downright grim and at other times tips into bathos.

There is so much potential - an ingenious stage set, committed actors, a cracking tale - but it is undermined by the inclusion of too many elements.

The pacing, too, is odd, with lines and action seeming either abrupt or drawn out.

As a result, the emotional intensity expressed is not always convincing and the central performances fail to grip the imagination as they should.