The case of a man who sold the rights to his mother's ketubah - on the presumption that she'll actually get it. And on the basis that he's not backing out even if his mother objects to it, but the son himself objected, once she died - as if on her behalf. Plus, what happens with the transfer of property with and without a guarantee for the purchase? Also, determining the extent of the rights of one who has purchased property with a guarantee, despite a creditor coming after the seller. What's the order for collection? Plus, a brief look at the Rishonim on this case.