A new mishnah - that facilitates a deeper dive into ma'amar, the Levirate betrothal. Via a case of 3 brothers, and the complications there that get in the way of yibum. Plus, the language of "kiddushin," a formal act of acquisition, and how ma'amar compares to kiddushin. Also, the undoing of vows that a husband can do for a wife.... Can a yavam do so for a shomeret yavam, a woman who awaits yibum? How strong is the bond between them to allow for this? And lo and behold, ma'amar has a role here too.