NOVA: Mysteries of Sleep Like virtually every other animal, humans need sleep to survive. But why? What do we gain from spending nearly a third of our lives in such a defenseless state? And what's at stake if we sleep poorly? The functions of sleep have long been something of a mystery. But now scientists are peering deep into the brain to see what happens while we snooze. One ...。Tara, a CIA agent, undergoes an operation that allows her to genetically morph into different people via DNA injections. This enables her to go into any country and "fit in" for any mission. However, when her dad dies mysteriously, Tara begins to question her superior/ controller, Hype, as she wades through treacherous international missions surrounding stolen minerals and nucl...。