The door to the guardroom opened suddenly and all eyes turned towards it as the duty officer, one of Severus’s optios, stepped inside and saluted Cato.

‘Sir, beg to report, one of the sentries says he has seen movement below the fort.’

‘Movement?’ Cato frowned. ‘What do you mean? Be specific, man.’

The optio was a young man, only a year or two older than Cato had been when he first held the rank. His anxiety was clear to see as he opened his mouth and tried to marshal his thoughts.

‘Just make your report, Optio.’ Cato forced himself to speak calmly. ‘What exactly has the sentry seen?’

‘He says there are men in front of the fort.’

‘He saw them? How many?’

‘He heard voices, sir. And horses. Then he sent another man to find me.’

‘And where were you?’

The optio took a quick breath. ‘In the latrine, sir.’

Cato bit back on his irritation. No doubt the optio had been spending the time with some comrades, in the way that many men did, in the traditional cosy camaraderie of the latrine block. It was far more comfortable to enjoy the banter in the warm and dry of the latrine than spend the night patrolling the windy ramparts of the fort. But that was no excuse. The optio was on duty. If he needed to piss then he could do it at the foot of the rampart. If he needed a shit, then he’d have to wait until he went off duty.

‘We’ll deal with that later,’ Cato said curtly. ‘Did you hear or see anything yourself when you got to the wall?’

‘I-I am not sure, sir.’

Macro’s patience snapped. ‘Either you did or you didn’t. Which is it?’

‘I thought I heard voices, sir.’ The optio glanced from Cato to Macro and back to the prefect.

Quertus laughed. ‘The fool’s imagining things. The river’s high. I’ve known men mistake the sound of a fast current flowing over the rocks for something else, and their imaginations do the rest. It’s nothing. Optio, go back to your duty and discipline your sentry. Perhaps a week cleaning out your shit in the latrine will cure him of his nerves.’

‘Wait,’ Cato interrupted. ‘You seem very sure of yourself, Centurion.’

‘Why shouldn’t I be? The Silurians are too frightened to show their faces in this valley. There’s been no sign of them anywhere near the fort in months. Your man is jumping at shadows. I thought legionaries were made of tougher stuff.’

Macro bristled. ‘There’s no better fighting man than a legionary. You’d do well to remember that, Thracian.’

‘Maybe, but there are clearly better sentries. Optio, tell your man to pull himself together and stop being a coward.’