Do our perceptions correspond to the real world - or are they merely a product of our brain? The documentary shows how neuroscience is attempting, by use of the most modern technologies, to decode the riddle of reality. Brain researchers say: We experience life within our brains. Every person constructs his own reality. More than that: Individuals can alter their perceptions, and even the structures of their brains, by the dedicated application of certain techniques; and, by so doing, they can actually create their own realities! As a result of these striking insights, science has regained its philosophical relevance, for questions are indirectly raised: In what kind of world do we wish to live? and: How do we wish to experience it?