En Jan Pol vol ser detectiu i està convençut que té tot el que li cal per convertir-s'hi. Fins i tot té el seu primer cas: descobrir qui s'ha menjat el seu entrepà de formatge. Segueix totes les pistes i les anota al seu bloc. Serà prou valent per arribar fins al final i deixar el cas tancat? Jan Pol wants to be a detective and is certain he has all the qualities necessary to make the grade. He even has his first case: finding out who has eaten his cheese sandwich. He follows the clues and makes notes in his notebook. Will he be capable of following the thing through to the end and closing out the case?