“The worst of all Handel's compositions” is how Charles Jennens, Handel's friend and the Messiah's librettist, described Handel's only operetta, Imeneo. On the other hand the cellist Thomas Harris, also a friend of Handel, commented, “I don't think it met with the applause it deserves, for there are many good songs in it”.

As for which man was right I'd say Harris, so for Imeneo to be the International Handel Festival's main theatre production this year is a thoroughly good thing. In fact, for 21st-century audiences its short running time – a thoroughly un-Handelian two hours are achievable – and unusually simple plot are positive draws.

Its starting point is a shipful of young Athenian maidens who, en route to a religious festival, are kidnapped by pirates. Unluckily for the pirates, one of their female captives is actually Imeneo dressed as a woman, which he's done to be close to Rosmene with whom he is besotted, but who in turn is already bethrothed to and in love with Tirinto. So, Imeneo slaughters the pirates as they sleep, and returns the ladies home. Don't get too excited about this rollicking romp of a yarn though, because none of it actually happens onstage. Instead, the operetta's three acts are all set in the same “lovely grove”, Act I kicking off as Imeneo lands his rescuees back on dry land and demands Rosmene's hand in marriage as a reward, which is granted on the proviso that Rosmene agrees. The opera then sees Rosmene agonising between her love for Tirinto and her duty towards Imeneo, her two suitors pleading their cases, whilst her friend Clomiri tries unsuccesfully to win Imeneo's affections for herself. Finally, having briefly feigned madness to buy more thinking time, Rosmene chooses duty and Imeneo.

All this throws up some interesting problems for a director to tackle, and not just the obvious one of how to keep an audience entertained through three acts of a woman in a garden trying to make up her mind. The “operetta” label suggests a certain amount of lightheartness, and there's plenty of scope for that, but how much genuine lightness is there in a tale of a woman rescued from a kidnap only to be emotionally blackmailed into becoming her victor's prize? In fact Handel hints at this himself by casting Imeneo as a baritone, when generally it's the higher-voiced males who get the girl.

So, any new production should fascinate, and Sigried T'Hooft's new production certainly does. Firstly, it seems that compactness isn't for her; she's lengthened it by adding ballet interludes danced by her Baroque dance company, Corpo Barocco, their music drawn from other compositions such as the Water Music and harpsichord suites.

The really striking elements, however, are the visuals. The singers employ Baroque performance gestures, complemented by a stunning Baroque-styled candlelit set and costumes by Stephan Dietrich. Intensely sumptuous and outrageously bright, the whole thing looks as if one of Watteau's fêtes galantes had sprung into technicolour life.

As for whether all the above works, it's a mixed bag. Taking the danced interludes first, whilst they're bound to be an opinion divider, the transitions are smooth, and the nod to the early operatic practice of punctuating performances with danced “intermedi” is rather fun. Then, the Baroque gestures look immensely right on this set, but without a working knowledge of the meaning behind each heavily stylised pose, some do seem dramatically inexplicable. Why, for instance, does William Berger's fine Imeneo have to freeze, coolly smiling with feet turned out and hand on hip, as Stefanie True's sprightly Clomiri swears she'd die for him? Still, you'd had to have had your eyes shut not to be moved by the anguished dignity with which Anna Dennis' Rosmene finally announces her marital choice. In fact, tone-wise the production manages to tread an elegant line between largely light but not comedic, and acknowledging Rosmene's sacrifice. As a result, when Berger and James Laing as Tirinto throw a comedic coup at the end, swapping vocal parts in mimicry of each other, it's all the funnier for its surprise factor.

The first night musical performances were similarly mixed. The chamber textures of much of the orchestral writing produced some lovely solo moments from the musicians of the Festival Orchester Gottingen under Laurence Cummings, and Anna Dennis shone vocally from start to finish. However, whilst Tirinto's jealously aria should have been a blistering highlight had there been any justice for Cummings and the orchestra, Laing appeared to be having an off night and only truly pulled things back for his final “Per le porte” duet with Dennis. This, though, was truly memorable for all the right reasons, their voices a perfect timbral dovetail, with some gorgeous ornamentation. In fact, for that one duet alone I'd return every night if I could.