In the spring of 2002, filmmaker Joe Berlinger traveled to Vienna to witness the burial of the preserved brains of over 700 children killed at a Nazi "euthanasia" clinic. GRAY MATTER chronicles the filmmaker's personal journey as he searches for Dr. Heinrich Gross -- known as the "Austrian Dr. Mengele" -- who allegedly participated in these killings. Along the way Berlinger meets survivors of the clinic, as well as other remarkable individuals, who are confronting a nation that has only begun to grapple with its denial of this horrific legacy.

In the spring of 2002, filmmaker Joe Berlinger traveled to Vienna to witness the burial of the preserved brains of over 700 children killed at a Nazi "euthanasia" clinic. GRAY MATTER chronicles the filmmaker's personal journey as he searches for Dr. Heinrich Gross -- known as the "Austrian Dr. Mengele" -- who allegedly participated in these killings. Along the way Berlinger meets survivors of the clinic, as well as other remarkable individuals, who are confronting a nation that has only begun to grapple with its denial of this horrific legacy.