Summer is the perfect time for murder. The members of the Walton Detective Society, Tom and Lily, face a seemingly impossible task: To find 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? And what about the gang that assaulted a jeweller and robbed him of his diamonds? How does all of this tie together? Tom and Lily will get to the bottom of all these mysteries if they escape being murdered themselves.