Doctors discover a shocking secret about a young mother dying of cancer.

A doctor investigates whether a rare disease drove a beloved physician to commit a violent murder.

A difficult-to-diagnose illness causes symptoms that mirror schizophrenia.

After several patients arrive at the emergency room with strange infections, the CDC Disease Detectives are called to investigate.

A rare genetic disease causes fatal insomnia.

Seven-year-old Kyle Lewis loves summer, then he develops a headache and a high fever, so his parents bring him to the hospital; doctors race to find out what is wrong with Kyle in time to save him.

A few days after the death of Dr. Autumn Klein, a doctor checks her chart to help solve the mystery of what killed her.

After patients present with similar symptoms, doctors have to act fast if they hope to save lives.

In Springfield, Mo., 61-year-old musician Mark Staudte dies suddenly, then his 26-year-old son, Shaun, dies five months later; Sarah, 24, falls ill nine months after her brother's death and is hospitalized in critical condition.

Physicians discover a strange, genetic disease that causes progressive neurological deterioration in children.

On Sept. 29, 1982, seven unsuspecting Chicago-area residents are stricken, and then die under mysterious medical circumstances. When the actual cause of death was discovered, a task force was formed to investigate.

High school volleyball player Jeanna Giese complains that she's fatigued and has numbness in her arm. When the 15-year-old starts experiencing double-vision and loss of balance, they know it is far more sinister than a sports injury.

What do California honeymooners, a surfer in Hawaii and a toddler in Tennessee have in common is investigated.

Dr. Bill Lidner was found by his daughters bleeding on the stairs of their home after a family trip abroad.

Paul and Alison Frase set out to find the rare dog that could cure their child's condition.

College student Lindsey Meyer and E.M.T Kevin Nesbit both come down with a painful sore throat. What seems like a symptom of the common cold, soon spirals into a life or death situation.

For thousands of years, the dreams and visions of the dying have captivated cultures. But what causes them? And are they real?