Twin Lakes is a tranquil place. It is a complex of holiday homes in a particularly beautiful part of England. "Rest Assured", says the sign at its entrance. And the people fortunate to occupy the luxury homes on the site are indeed able to relax in a beautiful setting. Then a series of mysterious threatening notes are delivered to one of the lakeside homes. DS Bert Hook conducts an informal investigation and the notes cease to appear. All is peaceful once more as spring moves into summer and the site is seen at its best. But suddenly a brutal death shatters the peace of this quiet place. As Lambert and Hook and the murder team investigate the crime, it emerges that the victim was by no means as innocent as most people thought him. And it seems that many of the residents lead far from ordinary lives and have secrets they will do anything to keep concealed.