Imagine a rich brew of Celtic mythology, Gothic horror and macabre comedy, sprinkled with sexual temptation, music hall routines and patriotic fervour, and you'll have some idea of the multiple strands that make up House of the Gods, brought to the Playhouse on Sunday by Music Theatre Wales.

Composer Lynne Plowman and librettist Martin Riley have thrown so many musical and dramatic ideas into this melting pot, it almost gives the impression that they are trying to use up all their creativity in one go. The result is an exhausting but compelling piece of theatre - in which, I have to say, the story had me gripped but Plowman's abrasive music was largely unmemorable, save for a rousing Act 1 finale that recalled patriotic melodies of the First World War.

Riley's plot is fanciful but accessible, and his libretto laced with dark humour. Set in 1916, the piece opens with reluctant war hero Jack returning from the trenches and having to busk in the streets to survive. He is drawn into the mysterious Halfway House, run by Ma and Da, two Celtic gods whose powers are fading. Their daughter Lily, virginal in white, appears sweet and innocent, but in fact is helping the sinister Uncle Crom with his scientific experiments in the basement. Perhaps predictably, Jack falls for the lovely Lily, and the pair discover that Crom is preparing a potion that lacks but one ingredient - the blood of a willing human sacrifice. The opera builds to a gripping climax as they battle to stop Crom's evil plan.

John Bishop's muted lighting and Colin Richmond's simple set capture the sinister atmosphere to perfection, and a talented ensemble get to grips admirably with the musical and dramatic demands made of them. Particularly outstanding are Mark Evans, who is vocally powerful and dramatically compelling as Jack, and Fiona Kimm, who delivers a robust and feisty Ma. A strange but interesting night out.