'Most days after school Harrie and Ben visit the Andersons' lolly shop on their way home. One day whilst they are there, they hear a loud bang outside. They are dismayed to discover that someone has graffitied the wall of the shop in bright red paint.
'After working their way through some clues, Harrie and Ben are convinced that the graffiti artist is a boy from their school. Could it be Noah, the quiet conscientious student who never does anything wrong? Could it be Alex, the bully? Or is it possibly Tony, the happy-go-lucky boy who has red paint all over his hands and arms?
'Tackling one of her hardest cases yet, Harrie looks at the evidence and works her way through the clues. Will she be able to figure out who the graffiti artist is?' (Publication summary)