Every Monday, Alan, Bill and Jim, the SIS (Special Individuals Society), go for uneventful walks in the beautiful countryside of the North East of England. Uneventful that is apart from getting lost, negotiating broken styles and fences, and encountering dogs and bulls! However, all that changes when Alan's grandaughter, Charlie, joins them during the summer holidays. This leads to the group being caught up in some decidedly dodgy activities taking place in the area, involving the local landowner, the 'one o'clock flight' and the mysterious green sheds. The result is a mixture of humour and adventure, as the SIS swing into action to solve the mystery, whilst continuing to deal with the normal hazards of their walks. 'Very good story line.' 'Had to keep reading to find out what would happen next' 'Captures the joys and perils of walking in the countryside.'