No Russian

No Russian. No Polish. Our driver speaks only German and our navigator speaks only English. None of us has any experience. We have a handful of tiny LED torches, a single working smartphone, and a rented van. We're woefully unprepared for this.

We don't even know what 'this' is yet. We're parked around the back of an abandoned hotel in Krakow at one in the morning. The briefing was heavy on the smoke bombs, flashing lights and megaphones, and light on the explanations. But we're cadets on the trail of mutants, looking for hidden codes that begin with EN, in a Russian game format called Encounter.

We hit the first location, a crumbling, abandoned fortress, lit only by our penlights. People call warnings - "step!", "huge drop!" - as we fan out to search it. Someone spots the code and we're on our way, doubling back briefly to try to throw other teams off the trail.

The code describes another fort, a kilometer to the west. I start puzzling over the map, but the driver has a hunch and takes us straight there. It's much larger, three stories, broken glass and dangerous holes in the floor. We need to split up to search effectively but I'm worried about the rumoured mutant attack, so we form into pairs. The cameraman sticks with me. I try not to think about the Blair Witch Project.

There are cries of "Team Eight!", our rallying call. Someone's found a QR code and taken a photo of it, but I don't have signal out here. We pile into the van and drive a couple of kilometers down the road, then pull a U-turn when the code leads to a map of the fortress we were just in, with a new location marked.

Back on the second floor, I realise that my squadmate is quietly attempting to search without a torch at all, and hand her mine, switching to my phone's LED flash. We spot something on the wall: EN.==.== . One four one four. We try that, unsuccessfully. Looking up a Braille reference guide gives me 1717; still no good. Simi splits the dots up differently, still wrong, but her idea gives me insight, and suddenly we've got it. EN .: :. :: is EN467. Code accepted. We high-five; it seems inadequate, but we need to stay quiet and move fast.

In the van, I brief the team on the newly revealed information. The mission: Contact a field agent. The location: Just an image, but we pass the phone around and someone recognises the street. The recognition symbol: we need to show the agent a dog. It's two in the morning in Krakow, and we need a dog.

Right. I grab the cameraman's spare mic and wrap it in my scarf, concealing all but the fluffy end, and pass it to Gabi. Then I spend the rest of the drive googling "small dog yapping sound effect". It's dark; we might get away with this.

We do. This time it's just a latitude and longitude, with the note "find the truth". Spraypaint on a tiny laneway leads us, single-file, into the woods. We couldn't have asked for better weather: it's foggy, and our flashlights make searchlight beams. A crew member waves us over and points out a no-go area, huge metal shapes looming over an open shaft. I can't get a sense of exactly how far the drop is without leaning over the safety rope. Fatal, certainly. We follow a trail of reflective tape, zigging and zagging, losing and finding the path, descending a steep slope to another mine site, and spread out to search. Someone spots a code taped to the inside of an overhead ore hopper.

"ENCIX". It's invalid. I'm not surprised; I was expecting digits. The team's on the move already and we're nearly out of time. I try EN109. Thought so. I log the code with a minute to spare and try to read the briefing for the next challenge without losing the rest of the team, walking fast along the dark trails.

We roll back to the Forum Hotel to defuse a bomb, for reasons I haven't had time to explain to the rest of the team, but which they don't really seem to care about. By the time we find it, another team has already disarmed it; we've come in third out of a field of perhaps ten. It's 3:30am, and I'm wide, wide awake, with a new contender for the best game I've ever played.