This is another good story from Nigel Tranter concerning an attempt to blackmail king James I by discovering Mary Queen of Scots famous but possibly incriminating "Casket letters" which she wrote to her lover Bothwell. Almost everyone knew that these were love letters;that they possibly admitted to foreknowledge of her hated husband Darnley's murder but did they also contain a confession that King James I, her son, was fathered not by Darnley but by her Italian secretary Rizzio?
This story stands on it's own but is more enjoyable if you have previously read N.Tranter's outstandibng depiction of King James and his courtiers in his other novels of the period starting with the marvellous Master of Gray Trilogy.
Excellent entertainment.