Paul and Barry install a safe for Dan the Van's Gran and discover a priceless ruby and some suspicious dinner guests.

The ruby has gone missing, so Paul and Barry visit the mill owner, Tatlock, who they believe to be the most likely suspect, on his own teritory.

Now they have the duplicate ruby, Paul and Barry recall all the original guests back to Gran's house on the pretence of a magic show by the illusionist, Stomoli.