A case of a Jew who is excommunicated because he's caused harm to another Jew, but via a non-Jew: selling a field that borders the property of Jew to a non-Jew. Plus, bees! And what happens when an aviary is on the border of one's property. Also, the Gemara's read of the mishnah's case of the bees. And to what extent casual conversation may count as testimony. And a second mishnah: When you see your stuff in someone else's possession. To what extent is robbery an issue in the place? That will determine whether the current owner needs to swear that he didn't steal them.