A secret from the past. An opportunity for blackmail. Set against the backdrop of the pharmaceutical industry, Adverse Reaction explores the complex relationship between two main characters Matt Pearson and Brett Chandler who met at university and then went their separate ways. When their paths cross some years later each character is driven by their own personal crisis to take desperate measures. Other characters become embroiled in the power struggle with serious consequences. Matt's desire to prevent his secret being revealed unleashes a dramatic sequence of events.