"A hand gripped her upper arm so suddenly it made her yelp. Biting her lower lip, she spun round, lashing out in terror. As she yanked her arm out of his grasp, her elbow hit the side of his chest. Struggling to cling on to her, he lost his footing. She staggered back and reached out, leaning one hand on the cold wall of the tunnel. Before she had recovered her balance he fell, arms flailing, eyes glaring wildly as he disappeared over the edge of the platform onto the rails below."

Geraldine Steel is plunged into a double murder investigation which threatens not only her career, but her life. When her previously unknown twin Helena turns up, her problems threaten to make Geraldine's life turn toxic in more ways than one.