When Lucinda Farrell's father, Miles Scott-Forbes, suddenly dies at the age of 77, there is a natural sense of grief but it is touched with a hint of relief on the part of Lucinda and her brothers, Tom and Harry. Miles was an eccentric, brilliant mathematician who hovered on the brink of madness, driving his family, sometimes cruelly, to distraction. But it seems, although he is now dead, that Lucinda is not going to escape from his machiavellian nature. He has left Lucinda a sealed box along with instructions to open it alone. Tom and Harry are in a fever of curiosity, tinged with jealousy. Why has Lucinda been singled out? Already her late father's actions are setting blood against blood. For Lucinda, the opening of the box will have shocking consequences...