After solving two of the most challenging cases of his career, Lieutenant Ed Cassidy finds himself, his wife and young son at the center of a vicious plot to avenge the horrific loss of a loved one. The maniacal chemical engineer, Melanie Taylor, was brutally murdered short of exacting her brand of vengeance, on those she held responsible for killing the object of her affection. Now the deep love and bond known only by close identical twins is the driving force behind the surviving sister’s heinous plans for revenge. She finds a way to add new chemical weapons to the Taylor sister’s arsenal, along with the evil ones developed previously by Melanie. Their wicked collection is at the center of existential threats being imposed on Lieutenant Cassidy’s world, beyond anything he imagined when deciding to join the police force. After years of reflection in sunny Tuscany, Italy, the only remedy deemed sufficient to satisfy a deeply devoted sister’s vision of justice, is her contemptuous Vendetta!