What is the plot of Dangerous Fortune by Ken Follett?

The story takes place at the Windfield School where a student, named Peter Middleton, has drowned. Edward, and his cousin Hugh, graduate and the action picks up with them attempting to struggle and attain control over a large bank. Edward seems to be close to acquiring it since his father is a partner there, but Hugh is the better banker.

Enter the mysterious drowning death of Peter Middleton (which happened many years previously). Peter's brother never buys that it was an accident and since two very influential and potentially wealthy people (Hugh and Edward) are involved, he threatens to reopen the investigation. Attempts to keep the truth buried result in several people getting murdered. In the end, the book, in true Follett fashion shows the powerful machinations that create large and powerful families and large and powerful businesses.....and the cost to do so.