She hurried downstairs. It was early afternoon, and just time enough to get out there and form the impressions that would help her when she went into action next day.

Taking a taxi to the railway station, she bought a ticket for the Circumvesuviana, the light railway that ran between Naples and Pompeii, taking about half an hour. For most of that time she sat gazing out of the window at Vesuvius, dominating the landscape, growing ever nearer.

From the station it was a short walk to the Porta Marina, the city gate to Pompeii, where she purchased a ticket and entered the ruined city.

The first thing that struck her was the comparative quiet. Tourists thronged the dead streets, yet their noise did not rise above a gentle murmur, and when she turned aside into an empty yard she found herself almost in silence.

After the bustle of her normal life the peace was delightful. Slowly she turned around, looking at the ancient stones, letting the quiet seep into her.

‘Come here! Do you hear me? Come here at once.’

The shriek rent the atmosphere, and the next moment she saw why. A boy of about twelve was running through the ruins, hopping nimbly over stones, hotly pursued by a middle-aged woman who was trying to run and shout at the same time.

‘Come here!’ she called in English.

The youngster made the mistake of looking back, which distracted him enough for Della to step into his path and grab him.

‘Lemme go!’ he gasped, struggling.

‘Sorry, no can do,’ she said, friendly but implacable.

‘Thank you,’ puffed the teacher, catching up. ‘Mickey, you stop that. Come back to the rest of the class.’

‘But it’s boring,’ the boy wailed. ‘I hate history.’

‘We’re on a school trip,’ the woman explained. ‘The chance of a lifetime. I’d have been thrilled to go to Italy when I was at school, but they’re all the same, these kids. Ungrateful little so-and-sos!’