From the time her son is born till the time he becomes an adult, his mother nurtures him and looks after his every need. The son gets so used to the mother's care that he can't do without her even after he grows up. He gets married and his wife takes his mother's place. A sense of insecurity develops within the mother and the question "Will my daughter-in-law steal my son away from me?" starts troubling her.
This thought produces a war between mother- and daughter-in-law, leaving the hapless husband caught in the cross-fire.