‘Orange?’ said Remi at breakfast the next morning. ‘How can the hair be orange? No trainee police dog has orange hair. Maybe Amadeus planted it there to throw us off the scent.’

‘Maybe,’ said Fizz, staring into the distance. ‘But one thing’s for sure, we’ve got to solve this mystery before anyone else gets hurt.’

Sergeant Stern appeared at the dining hall door. ‘Finish your breakfast and meet me in the quadrangle for training. We’re going to start the day with a game I like to call Guess That Scent.’

Sergeant Stern had arranged four small boxes on a low table.

‘The aim of the game is to guess what’s in the box by using your sense of smell. Remi, you may go first,’ said Sergeant Stern.

Remi trotted forward and smelt the first box.

‘Chocolate,’ she said.

‘Very good, Remi,’ said Sergeant Stern. ‘Now the other boxes?’

‘Peanut butter, sunscreen and…soap?’ said Remi.

‘Close, the last box was talcum powder,’ said Sergeant Stern, putting out four new boxes. ‘Your turn, Amadeus.’

Amadeus strutted up to the table. ‘Watch and learn, Powder Puff,’ he growled in Fizz’s ear. ‘Too easy. That’s bubble gum, fertilizer, broccoli and basil – actually, purple basil, Sergeant Stern.’

‘Excellent, Amadeus. Molly, your turn.’

Molly was a Golden Retriever with a good nose for food. ‘Baked beans, cinnamon, strawberry, and…’ Molly sniffed the last box. Her eyes bulged and her nose turned red. She shook her head violently and sneezed.

Sergeant Stern opened the fourth box. ‘Crushed chilli pepper!’ he cried in disbelief. Sergeant Stern fetched a cold cloth and wiped Molly’s nose.

Fizz checked out the box. Stinging red-hot chilli peppers.

‘Fizz, take Molly to the vet clinic. The chilli peppers have burnt her nose. The rest of you can practise your attack skills in the recreation hall.’

Fizz walked Molly to the vet clinic, where Ms Jabb examined her nose.

‘Is she going home?’ asked Shamus, who was playing with a pink squeaky toy.

‘Yes, Shamus, and will you please put that toy away. I can’t think with all that squeaking!’

Sergeant Stern arrived to check on Molly. Ms Jabb was putting burn cream on her nose.

‘Perhaps it’s time to get a guard dog, Sergeant Stern,’ suggested Ms Jabb. She had a brochure with a picture of a fierce red Ridgeback on the front.

‘Guard dogs for hire,’ read Sergeant Stern.

Fizz recognised the dog. It was Razor! The perfect job for him, thought Fizz.

‘I don’t think that will be necessary,’ said Sergeant Stern.

‘Six dogs sent home and six dogs from the waiting list called in to replace them. You’ll be calling Shamus next, heaven forbid,’ said Ms Jabb.

Shamus made a loud slurping noise as he chewed a treat.

‘Shamus, will you stop eating all my treats!’ said Ms Jabb. ‘You’ve already lost three front teeth. Too many biscuits are not a good thing. Here Fizz, take the treat box and share it with the other trainee dogs. I’m sure they’re in need of a pick-me-up about now.’

Ms Jabb looked at Sergeant Stern.

‘I’m very worried about the safety of my Shamus and the other dogs.’

‘I know. But I have every confidence our trainee undercover police dogs will get to the bottom of the matter,’ said Sergeant Stern, giving Fizz a look as he left.

Fizz gulped. He had no new clues and he wasn’t any closer to solving the mystery.