The reported sighting by a fellow pupil of a ghost in the disused science block, compels private detective Moon to try to become a temporary psychic investigator. April challenges Moon to prove that Devlin has made up the appearance of evil old Mr Pickles. Initially sceptical, Moon find his beliefs challenged when "evidence" of the supernatural seems to present itself. It's time for Moon and Red to set up a stakeout in the old lab. Armed with various gizmos designed to record evidence of paranormal activity, they wait. But things are not quite what they seem. Green smoke, mysterious banging and a gruesome monster - will the boys solve the mystery?