In 1910, while hiking through the wild lavender in a wind-swept, desolate valley in Provence, a man comes across a shepherd called Elzéard Bouffier. Staying with him, he watches Elzéard sorting and then planting hundreds of acorns as he walks through the wilderness.

Ten years later, after the war, he visits the shepherd again and sees the young forest he has created spreading slowly over the valley. Elzéard's solitary, silent work continues and the narrator returns year after year to see the miracle he is gradually creating: a verdant, green landscape that is a testament to one man's creative instinct.