As I was preparing to leave work last night, I got a notification that “wherenext” had followed me on Twitter.

@wherenext’s profile sent me off to What is the question?, which appeared to be a Masquerade style treasure hunt. Presented with clues, the task is to find 43 object hidden in a square mile of London – the very part I travel to every day.

The clues stumped me for a bit but eventually I worked out they were referencing various blogs (had I seen the Guardian story previewing the game I’d have been there quicker!). These blogs have within them pointers to locations on the map. I discovered that one of the locations was behind my office and another couple on a (slightly circuitous) route home, so I passed by all of them in the evening darkness – and found nothing.

Before I go on I should mention – as the Guardian article explains – that the game is promoting the campaign site XDRTB.org, which is creating awareness of extreme drug-resistant tuberculosis. It was set up by photojournalist James Nachtwey, who captured these harrowing images:

Last night, I worked on the clues and came up with most of the locations, with a clear pattern forming on the map. I got up at a quarter past six this morning to catch an early train and begun by traipsing around Waterloo armed with my mobile phone’s GPS and Google Maps.

I wasn’t sure how hidden the items would be and didn’t really want to draw attention to myself (even at 7am there were people around) so I didn’t clamber around the first grid point too much. Probably as a result, I didn’t find whatever it was I was looking for. I’d seen something on Twitter about photographing yourself in the location even if you didn’t find the object, so I did that:

A short walk away at the next location, I again failed to find anything. And then, after a longer walk, I found myself on the south bank of the Thames opposite the House of Parliament.

Failure there too.

Next stop was York Road, ascertained from a clue on Bill Thompson’s blog. I peered around as nonchalantly as possible as commuters from Waterloo passed by. And there, concealed behind a plant pot, I found…

Each photograph is accompanied by a character, in this case an O, and the 43 characters will make up a question. Identifying that question is the key to winning the game.

The excitement of this discovery – photograph quickly moblogged – was quickly followed up with more failures, and a while later with two more successes, one near Embankment tube and one close to Parliament Square. I was impressed that the team behind the game had managed to place so many objects in sensitive areas without causing security alerts (yet).

I covered around 20 sites and around 7 miles in more than two hours of hunting, got plenty of exercise (not least lugging my laptop with me) and got to know bits of London I pass near every day in much more detail (including passing through Horse Guards Parade for the first time).

At lunchtime I returned to a couple of the sites from last night and found the daylight made all the difference: two more successes. At the time of writing, nine of the objects have been revealed.

I’ve now solved (hopefully correctly) all the clues and identified 43 locations. To help me track down the objects, I’ve programmed the locations into Google Maps on my phone, and they appear to form a recognisable pattern:

There are 15-20 locations I’ve not been to yet. I’ll see if I have the energy for another early start tomorrow.

And, of course, you can play the game too…