‘PC Plod has just been told to go to the manor house,’ said Artemisia. ‘Immediately!’

‘Do you remember what was missing from the house?’

‘A pearl necklace belonging to Lady Doubtful.’

‘And what’s the name of PC Plod’s wife?’

‘Beryl!’ said Artemisia. ‘She thinks he ought to be an Inspector.’

William nodded, and began to read.

‘When PC Plod arrived at the manor house, he propped his bicycle up against the shed and joined the other policemen, who were searching the grounds for clues. He doubted they’d find any, as he was sure it was an inside job.’

‘What’s an inside job?’ asked Peter.

‘PC Plod thinks someone who lives or works in the house must have stolen the pearls.’

‘Who?’ demanded Artemisia.

‘I’ve no idea,’ said William, stifling a yawn as he turned the page.

‘But you’re a detective, Daddy, so you must know,’ said Artemisia, with the unquestionable logic of a child.

‘PC Plod noticed the front door of the manor house open,’ continued William, ignoring her, ‘and saw a scullery maid who’d served the Doubtfuls for years being led out of the house by Inspector Watchit, who looked rather pleased with himself. Plod frowned. He knew that Elsie wouldn’t have stolen a chocolate biscuit from a tea trolley, let alone a pearl necklace. He would have to go back to the station and put Watchit straight, before he charged the poor girl with a crime she hadn’t committed. He left the lads to get on with their job, and walked back to his bike. He was about to put on his safety helmet when he spotted a fishmonger’s van coming up the drive to deliver the catch of the day. Plod was surprised to see Mr Nettles the fishmonger park his van right outside the front door and not at the back of the house by the kitchen entrance. Nettles got out of the van and strolled up the steps to the front door which was opened by Lady Doubtful even before he had a chance to press the bell. Her Ladyship handed the fishmonger a large cardboard box, then quickly disappeared back inside.

‘Why hadn’t Nettles gone to the tradesman’s entrance and delivered the fish to the cook as he did every Friday, wondered PC Plod. It didn’t make any sense, so he decided to investigate. Plod plodded across to the van, where Mr Nettles had left the cardboard box on the passenger seat and was now sitting behind the wheel about to leave.

‘Plod tapped on the window and said, “What are you up to, my lad?” Nettles turned as red as a traffic light. He quickly switched on the engine, crunched the gear lever into third, and shot off towards the front gate. Plod dashed up the steps to the house and banged on the front door. When the butler opened it a few moments later, he told him to quickly close the electric gates. The butler touched the switch just in time to prevent Nettles from getting clean away.