I led the way out into the street, called a fiacre, and whispered an address into the driver’s ear.

It was my turn to enjoy the discomfiture of my colleague, as the carriage drew up before his own door.

‘Here!’ was all he could gasp.

I paid the driver and dismissed him.

‘Surely there could be no spot more safe from the perquisitions of the police,’ I answered mockingly.

M. Rattache conducted me in, and led the way towards his study.

‘Not that way,’ I objected. ‘It is necessary for us to go upstairs.’

With ever-deepening chagrin M. Rattache followed me, as I ascended to the schoolroom in which his little daughters were at play with their dolls.

They rushed to embrace me with exclamations of joy.

‘Isabel,’ I said to the eldest, a bright girl of twelve, ‘now you shall show the others the hiding-place where we put the box of bricks.’