Found my flashlight.

I'm back. I've had a shower and something to eat. Most of the equipment is still downstairs.

It took several trips to get the supplies to the bottom of the stairs. I left the water against the first step and put the food and batteries beside it. Having somewhere to leave things made a difference. I could take a smaller bag into the passages and come back to sleep.

For the first few days, the notebook helped. I numbered each junction, drew the turns and wrote down anything I thought might distinguish one stretch from another. There wasn't much. I started putting a small chalk cross beside passages I'd already checked.

I found some dead ends and a few routes that joined up again. Once I'd worked those out, I felt better about being there. I could look at a number on the wall and find it in my notes.

Then I found the flashlight.

It was lying near the left wall, a little way past a corner. I nearly walked past it because my headlamp was pointed further ahead. I saw something catch the light, went back and picked it up.

It was the one I dropped when I ran back to the basement.

I'd looked for it along the first corridor on my way in. I hadn't found it, but I'd assumed I'd missed it. I was carrying things and stopping to put up the reflective markers.

This was well beyond the stairs. I'd crossed the large room, followed the wall and gone through several junctions to get there.

I sat down with the light and my notebook. I went back through the pages, checking the numbers against the last few marks I'd passed. I couldn't find a mistake that would explain it.

Eventually I decided I must have found another way around. Perhaps one of the passages sloped upward so gradually that I hadn't noticed. If I was back in the first corridor, the basement opening should be somewhere ahead.

I left my bag at the corner, marked it clearly and carried on with a spare light.

I walked much further than I expected to. Kept looking for the little pale shape of the opening. I even switched my light off for a moment in case the basement light was too faint to notice otherwise.

There was nothing ahead.

A little further on, the passage ended at a wall.

I checked both sides in case I'd passed an opening. Walked back slowly, looking at the floor and the walls. There were no stairs, no way through. Eventually I reached the bag where I'd left it.

I followed my marks back to camp. Every junction was where I'd written it down. I came out into the large room and followed the arrows across to the stairs.

I checked the notebook again after eating. Then I packed what I could carry and went home.

The flashlight is on the kitchen table now. The batteries were dead. I put fresh ones in and it works.

I keep laying the pages out beside each other, trying to make the route meet up somewhere. So far I can't do it without drawing a connection I never walked through.