‘A point to note,’ he said, gesturing down at the blue surface of the lake. ‘If you’re ever out huntin’, don’t be tempted to stop at a place like this, either to take in the view or to get a better look at the surroundin’ terrain. Imagine what we look like to any animal in the forest, silhouetted here on the ridge. We can be seen for miles.’

Before Sherlock could say anything, Crowe started off again, pushing through the undergrowth. Sherlock wondered briefly how the man knew which way to go without a compass. He was about to ask, but instead tried to work it out himself. All Crowe had to go on was their surroundings. The sun rose in the east and set in the west, but that wasn’t much help at lunchtime when the sun would be directly overhead. Or would it? A moment’s thought and Sherlock realized that the sun would only be truly overhead at noon for places actually on the equator. For a country in the northern hemisphere, like England, the nearest point on the equator would be located directly south, and so the sun at noon would be south of a point directly overhead. That was probably how Crowe was doing it.

‘And moss tends to grow better on the northern side of trees,’ Crowe called over his shoulder. ‘It’s more shaded there, and so it’s damper.’

‘How do you do that?’ Sherlock shouted.

‘Do what?’

‘Tell what people are thinking, and interrupt them just at the right moment?’

‘Ah,’ Crowe laughed. ‘That’s a trick ah’ll explain some other time.’

Sherlock lost track of time as they walked on through the forest, but at one point Crowe stopped and crouched down, putting the basket down.

‘What do you deduce?’ he asked.

Sherlock crouched beside him. In the soft ground beneath a tree he saw a hoof print, small and heart-shaped.

‘A deer went this way?’ he ventured, trying to jump from what he saw to what he could work out based on what he saw.