Nadia writes down everything that happens at the Marrow Lane allotments. So she's the first to spot it: Mr. Okafor's giant champion pumpkin moved overnight. Not gone, just sitting three plots away in Mrs. Pratt's strawberry bed, plump and shiny with dew. By morning both grown-ups are yelling at each other. Nadia opens her notebook and starts writing.

Nadia decides to question the grown-ups first. Mr. Okafor swears he locked his gate. Mrs. Pratt swears she'd never touch his ugly pumpkin. But Nadia notices old Mr. Bell two plots over, very quiet, suddenly very interested in watering plants that were already wet.

Nadia checks Mr. Bell's plot while he's not looking. Behind his tomatoes she finds his own notebook, full of pumpkin sketches and the words 'biggest ever seen.' He isn't the thief, just a fan. Then she spots small footprints by the fence, follows them to the Lim kids, and the truth comes out. Mystery solved.