Two men—a meticulous physician and his younger companion—become lost in the vast redwood and fir country of northern California and set out to find shelter by following a wisp of smoke. Their wanderings bring them into contact with eccentric locals, prospectors, and a small mountain community, and embroil them in episodes of danger, wilderness survival, and regional folklore. The narrative moves through conferences, riddles, secret caves, a drifting episode on a river, and strange messages or tablets that deepen a quiet mystery. Interpersonal choices and alliances among residents, including a woman named Mary, shape the group's fortunes as they navigate hazards and revelations in the mountain valley.