Art Bell opens with current events, including President Bush's stem cell research decision, a Jerusalem bombing, record-breaking heat waves, and cattle mutilations in Montana. Open lines bring in colorful stories, from a 1950s balloon adventurer to reality TV debate, before the conversation shifts to the mysteries of the red planet.

Richard C. Hoagland joins to present what he calls a solution to the mystery of Mars. He traces the history of Martian exploration from the canal debates of the early 1900s through the Mariner and Viking missions, recounting his firsthand experience at JPL during Viking's 1976 landing. He examines Gilbert Levin's Labeled Release experiment, which detected what appeared to be biological activity in Martian soil, and new analysis by neurobiologist Joseph Miller showing circadian rhythms in that 25-year-old data.

The discussion expands into evidence of liquid water seeping from underground on Mars, with Hoagland presenting images of dark stains flowing downhill on the Martian surface. Art and Richard explore the implications for life, terraforming, and what the death of a once-vibrant world might teach us about protecting our own planet from a similar fate.