The Anderson family, a father (James Stewart), his six sons, daughter and daughter in law, try to sit out the war (u.s. civil) on their Virginia farmstead. He won't side with the south because he doesn't agree with slavery etc, but he won't fight against his homeland either.
Others try to entice him and his sons to join the southern cause, leading to some poignant and at times humorous moments, but as long as folk stay off his land and leave his family be he's not interested.
Not long after becoming a granddad, his youngest son is taken prisoner by union troops, so leaving his son and daughter in law to care for the farm, the rest of the family set off in pursuit. At this point the film splits, focusing sometimes on the boy, sometimes on the family. Having exhausted all possible leads in his attempts to find the boy, he leads the party home, to catastrophic effect.
The final ten or so minutes of the film are a real mixed bag of emotions, the scene at the family grave, where his wife has now been joined by his two eldest sons and his daughter in law, and maybe the boy is touching, then the church bells ring! "why didn't somebody tell me it was sunday", he rounds up what is left of the family and leads them off to church (late as usual) for a surprise ending.
My favourite J.S. film, which sees him wrestle against not only outside circumstances, but also his conscience.