Bill Nye explores the concept of life on other planets by taking us everywhere from Earth's oceans and deserts to Mars and beyond.

Bill shows that astrologers and tarot card readers are doing nothing other than making vague guesses, and that walking on fire without burning your feet is scientifically possible and does not require any sort of spirituality.

Bill argues that addiction is a disease by using scientific instruments to show that the part of the brain responsible for weighing actions against consequences does not function properly when one is addicted to drugs. Bill also shows that part of getting drunk is largely a placebo effect, by letting a group of people drink beer without them knowing it is non-alcoholic. Finally, a theory is presented as to why the part of the brain responsible for making us addicted to things has not faded away over time.

The possibilities of cloning reach far beyond creating genetically exact duplicates of animals or human beings. The same techniques could potentially be used to cure diseases or repair damaged organs. Bill talks with a developmental biologist about why cloning animals is so difficult, shows how cloning works, and visits a lab where stem cells are used to repair damaged spinal cords.

With evidence of global warming mounting, Americans are revisiting the idea of nuclear energy. It's a clean energy source that can be produced domestically, but dealing with the waste remains a major hurdle. To find out whether the benefits are worth the risks, Bill visits a nuclear reactor and the Yucca Mountain, NV site where the U.S. government wants to store nuclear waste.