1915. Life at the Paridier farm has changed dramatically since the men of the family left home to go and fight on the front line. Hortense Sandrail, Henri and Constant's mother and Clovis' mother-in-law, has taken over courageously but, although helped by her daughter Solange, she finds it hard to get by with all the workload. When harvest time comes, she makes up her mind to hire a farmhand but she is too late and no man is available. The mayor then recommends her an orphan named Francine Riant, who could do. Hortense agrees and the choice soon appears a blessing, as the girl proves perfect: well-mannered and respectful, she is also a hard worker who does not balk at any task. Hortense, Solange and her form an effective trio, who make the most of the situation. One day, Georges comes back to the farm on leave and he falls in love with Francine.
Based on the novel by Hannelore Cayre, the story centers around Patience Portefeux, an underpaid, overworked French-Arabic translator in charge of phone surveillance for a narcotics police unit. When she realizes she knows the mother of one of the drug dealers, Patience decides to cover for him and gets herself more and more deeply involved in the world of drug trafficking. Soon, she is using her insider knowledge and police resources to build her own crime network and earns the name Mama Weed.