The Master of Gray is the principal character (incredibly ambitious ,confident courtier who is involved in all kinds of plots and skulduggery) in the trilogy which covers the period from when a teenage James, at first, attempts to break free from his advisers to rule on his own.It describes in detail the attempts to have his mother Mary Queen of Scots freed from Elizabeth's clutches, and finally concentrates on the efforts to have James succeed Elizabeth and ends with James crossing into England. So you may not be particularly interested in the first half of the trilogy. But N.Tranter paints a splendid portrait of Mary,Elizabeth but especially of James and really brings them alive.
An incredible picture of the Scottish witch trials under James is also depicted. I thought that Tranter was surely exaggerating in order to create extra interest for his readers but I did a little research when I had finished the trilogy and was surprised to see that everything was historically accurate ...an amazing period.James who was a very intelligent,well educated but crafty individual, regarded himself as an authority on witches and wrote a very learned tome on the subject.He was convinced that Satan had it in for him personally as he was" Christ's vice- regent" on earth

N. Tranter wrote The Wisest Fool approx.ten years later (early 70s) and picks up exactly where he left off, at the crossing into England. This time the principal character is James's jeweller/banker, with life in the London court as background.
I found the trilogy especially a fascinating read .Some people have found Tranter old fashioned and dry to say the least but to me he's incredibly detailed and rich but one mans meat ... so I hope you enjoy if you go ahead.