James W. Lewis is portrayed as the main suspect in the Tylenol Murders case. He is known for sending an extortion letter to Johnson & Johnson demanding $1 million, which made him a person of interest for over 40 years. The series features interviews with Lewis himself, where he explains why he could not be the Tylenol murderer, providing insight into his character and involvement in the case.

The victims are connected by having ingested cyanide-laced Tylenol capsules. A particularly chilling plot element is the simultaneous deaths of three members of the same family—Stanley Janus (25), Adam Janus (27), and Theresa Janus (20)—which was a key factor that alerted authorities to the unusual nature of the deaths.

The series explores controversial points including the potential involvement or negligence of pharmaceutical giant Johnson & Johnson. It delves into how the company responded to the crisis, the safety precautions they implemented afterward, and the suspicions around whether an employee or someone with a grudge could have been involved in contaminating the Tylenol capsules.

The series includes powerful interviews with people who knew the victims and journalists who covered the case, showing the human cost of the tragedy. For example, the story of Paula, a victim who died alone and was captured on store camera footage, is highlighted as particularly tragic and chilling. These scenes emphasize the indiscriminate and devastating nature of the crime.

The series portrays the investigative process, including how authorities identified the link between the deaths and Tylenol capsules laced with cyanide. It also shows the challenges of communicating such a crisis in 1982, before the era of 24/7 news, highlighting the various methods used to alert the public and manage the unfolding emergency.