A searing scientific murder mystery packed with heartpounding twists.

It is 1965, and in Holloman, Connecticut, someone is preying on the innocent. At a prestigious research centre for the neurosciences, fondly known by its staff as “the Hug,” parts of a mutilated body are discovered. Very soon Lieutenant Carmine Delmonico of the Holloman Police learns that a string of horrifying murders, each fitting the same modus operandi as the body found at the Hug, has been occurring throughout the state. Then another body is found and the medical staff become prime suspects...

With the Center’s hierarchies of power in turmoil and every member of its staff hiding something, Delmonico delves into the lives and pasts of each and every employee. It is the case of his career, and he is determined to solve it. But how do you find a monster who leaves no clues and is always two steps ahead?”

Colleen McCullough artfully maintains the suspense and holds back the truth until the last page, where she presents the reader with one final terrifying and unexpected twist.

On, Off is a classic murder mystery, written with all the flair and skill that have made Colleen McCullough one of the most popular novelists of her time.