In the summer of 1990, Timothy Treadwell ventured into the Alaskan wilderness to live among its grizzly bears. He returned yearly, until his 2003 death (with girlfriend Amie Huguenard) at the claws of one of the creatures he sought to befriend, to protect and, on some level, to become. "Grizzly Man" is a brilliant portrait of adventure, activism, obsession and potential madness.