Wow, what a trip! The reviews I found online used a lot of phrases like "impenetrable" and "incomprehensible", but Jonathan, Christopher and I understood it instantly -- this was basically an operatic re-telling of the same ancient Chinese "Monkey King" legend which served as the basis for the hit manga/anime Dragonball, as well as theatrical movies like the recent "Forbidden Kingdom."
If you're familiar with Dragonball, rest comfortable knowing that featured characters in the musical (under different names), included Son Goku (complete with tail, flying nimbus, and extending staff), Oolong, Piccolo, Roshi, and Shenlong, and that among the missions Goku had to accomplish was finding a magic fan to extinguish a flaming mountain (c.f. episode 7, "Furaipan Yama no Gyūmaō").
The entire show was spoken/sung in Mandarin Chinese, with typically head-scratching subtitles displayed on large side monitors. The presentation was basically similar to a Cirque du Soleil, with climbing ribbons, lots of high-wire flying, martial arts and swordplay, and a large backscreen where animated footage was used for cut-scenes and to interplay with the live action on-stage.
This didn't take place in the Dome's mammoth central arena; we were in an off-shoot around back, which was actually very cozy as it meant that even cheap seats were quite close to the stage. All told, it was an awesome sight, highly recommended if you have a bent for subtitled anime opera (and who doesn't?!?)
Subplot: actually getting to the O2 from the Tower of London proved rather a story in itself, as the Jubilee Tube line was down. We ended up walking to the London Bridge tube station, taking National Rail to Greenwich, then riding the DLR (Docklands Light Railroad) up to Canary Wharf, which was quite interesting but not where we were supposed to be; so back on the DLR down to Cutty Sark, and finally a double-decker bus up to the O2. Coming home we attempted to reverse our steps, but ended up riding the bus all the way to Waterloo (and thence on to Paddington via Bakerloo). Happily we had a wonderful and piping hot Thai dinner before the show, which helped ward off the chill during our many wanderings!