If you've ever seen the musical Evita, you'll surely remember its weirdly unsatisfying conclusion. Having witnessed the rise and fall of Eva Perón – the controversial, mercurial, popularly-adored first lady of 1950's Argentina – we're informed as a parting shot that, after her untimely death, her body disappeared for 17 years. I've always wondered: why stop the story there? And now, thanks to this detailed piece of storytelling from Firefly Theatre & Circus, I finally know the ending.

Operation EVAsion does warn us that we shouldn't take Evita too literally, but this script feels solid, well-researched, and entirely believable. In the febrile, revolutionary atmosphere of mid-century Argentina, Eva's body became a political pawn; its disappearance denied the still-powerful Peronist movement a totem to gather around. Bizarrely, there wasn't just one body, but four – the real one and three replicas, so perfect in their mimicry of the embalmed original that only an X-ray could distinguish them from preserved flesh and bone.

The story is told in the first person, from the perspective of the body and its doubles, by an actor who hangs ethereally – trapped between Heaven and Earth – in an aerial sling. Annie Dugan delivers a convincing and engaging performance, which educates us on Argentinian politics without degenerating into a lecture, and particularly highlights the paradoxical relationship between Eva and the Argentine military. They hated what she stood for, and therefore they hated her – yet they seem almost besotted by her legacy.

There are some neat projection tricks to bring other characters into the heart of the story, and the sling is used to its full potential: sometimes it conceals Dugan, sometimes it supports her, sometimes she unfurls it, sometimes she uses it to symbolise a world closing in. In other ways, though, this approach is quite limiting – an actor's dramatic range is inevitably constrained when they're confined to a single place, and swathed in a fabric cocoon. I loved it for a while, but after that while, I longed for more variety than I saw.

Jason Kodie's tango-infused live accompaniment is a delight, but over time, it too loses its impact. A scene where Kodie leaves his seat to approach Dugan mixes it up a touch, and a few more interludes like that one would have made all the difference for me.

I enjoyed Operation EVAsion as an illustrated talk, and as a demonstration of aerial work – but as a theatrical performance, it felt a little light. Nonetheless: this is a fascinating story, and if the history piques your interest, it's well worth hearing it told.