This forest is full of invisible lines. There is the line of the U.S./Canada border, which Mike needs to cross undetected with his rucksack full of shrooms. There are the myriad underground lines of mycorrhizal fungi connecting the trees into a powerful network. There are the lines linking Homo sapiens with nature, a web of interconnectivity and failed responsibilities. Mike enters the forest as one person and exits as another. Over two hallucinatory days, Mike must learn to listen to the forest's voice. If he can't hear its message, all of humanity will have to pay the price. The message the forest has for him is this: There are some lines that must never be crossed.