The situation is straight out of an early Shakespeare comedy: two babies are switched at birth by mistake in a maternity ward, such that a Jewish Israeli family raises a young Arab and a Palestinian family raises a young Jewish Israeli. Just short of their 18th birthdays, they learn the truth.
The first part of the movie deals with the reactions of the four parents. All four actors give truly moving, first-rate performances. The Jewish father is an officer in the Israeli army, someone who has spent his life fighting Arabs. Still, he is torn apart by what he perceives as the loss of his son. The Arab father doesn't know how to react: is he now harboring a hated Israeli in his own poor home? But he, too, loves his son very much, and cannot deal with the thought of losing him.
The two mothers also experience a feeling of loss, but are able to speak to each other in ways that the two fathers, for political reasons, cannot.
The son of the Jewish couple finds acceptance in the Palestinian family through a mutual love of music. It is less clear how the son of the Arab couple will fit in the Jewish family. Will Yacine be able to tolerate living with an Israeli army officer? How will his family deal with that? The movie, as I said, is based on a clichéd theatrical device, but there is nothing clichéd about the acting or the script here: it all seems very real, and often very intense. It never seems fake. Unlike what the other two reviews suggest, not everything is resolved here by the end of the movie. That would have been too pat, too American-TV.
I strongly recommend this movie. It's really well done.