Dexter had been looking forward to eating his sandwich all morning.

He plucked it from his lunch box and held it up to the light to examine it. The thick white bread was as springy as a mattress with curling sheets of crunchy lettuce poking from between the slices.

Dexter’s mouth watered. He knew that nestling between those delicious slabs of crusty bread was his favourite ever sandwich filling; a filling so tasty, it was dangerous. Deadly dangerous.

Dexter’s deadly sandwich fillings were banned in six English counties. Ever since he’d created his first masterpiece, the word had got out that trouble was in store for anyone tempted to nibble on one of his brilliant butties. And no one liked trouble, especially not trouble in a sandwich as sandwiches are the friendliest kind of food.

Dexter’s eye twinkled with glee as he brought his latest glorious delicacy to his mouth. The lettuce leaves shimmered in the sun streaming through the window into the dinner hall; the white bread was as light as a cloud on a summer’s day. After one last glance at the children sharing his table, Dexter crammed a corner of sandwich into his mouth, clamped his eyes closed and crunched down hard.

Outside, all the leaves fell off all the trees at once.