A sweltering day in Florence, and newly-wed art student Mary Warren breaks away from her tour group in the Boboli Gardens to wander into a shady tunnel of trees. But the tranquil setting conceals a complex maze and a masked killer: within minutes Mary has been severely attacked and her husband brutally murdered.

A year later and the 'Honeymoon Killer', Karel Indrizzio, is dead and Mary is living a restless life in Philadelphia. Her scars are a constant reminder of that dreadful day, but in an effort to help her forget, her friend - attractive journalist, Pierangelo - invites her to return to Italy.

However, in this city Mary's dark secret cannot stay buried for long. For there is a new menace stalking the women of Florence, and his technique is startlingly reminiscent of her own attacker's. Piero is following the deadly trail and Mary soon recognizes terrifying implications and patterns in his research: either this is a copycat, or her husband's murderer is still at large . . .