Pine Marten tells of two people dealing with a soul-shattering tragedy in the Missouri wilderness of 1855. Woodcutter Salem Greene leaves his family alone for two days, then returns to find his wife and nine-year-old daughter brutally raped and murdered. His son is missing, presumed dead. Greene finds the perpetrators, but the horrific way he exacts retribution makes him feel unfit to live with others. He goes into exile and tries desperately to forget his past. Unbeknownst to Greene, his twelve-year-old son Martin escaped and lives in a cave two miles away. Naked but for a ragged bloody nightshirt, and defenseless except for a butcher knife, Martin engages in a primal search for food by day. At night, he hides, terrified by what lurks outside the cave. One trying to escape the past; one searching for a future. Will their paths cross again?