When Tom and Lily set up the Walton Detective Society in the Spring of 1938, they did not expect that they would spend much of their summer chasing thieves and murderers. The facade of famous Walton College of Rompchester University hides many ugly secrets. Many more than they ever expected.

Summer is the perfect time for murder. Tom and Lily face a seemingly impossible task: To find out a murderer who committed the perfect crime. When all their means of detection are exhausted, Tom and Lily refuse to give up. Instead, they devise a clever scheme that sets a trap for the murderer. Will he fall into it? And what about the bomb-blast that blew the window of a don to smithereens? What about the gang that assaulted a jeweller and robbed him of his diamonds? Tom and Lily will get to the bottom of all these mysteries provided they escape being murdered themselves.