The daf explores the idea of Mi Sh’Para and what happens of someone reneges on a sale and the beit din cannot enforce the sale.

Defining "kinyan sudar" - a handkerchief version of halipin. Plus, "kinyan agav," where the act of acquisition is secondary and along the way of the acquisition of something else, usually movable items along with a purchase of land. Also, using exchange when you have no money or anything else of value to use for purchase.

More on exchange - including the question of using a coin as an indication of a formal act of acquisition. For it to work, he has to already have the coins in hand. Otherwise, it's too close to a sale. Also, Rav Nachman's opinion, the idea that money does effect the purchase by Torah law, and the exchange of money bags.

One who redeems ma'aser sheni on coins, and the desacralizes the coins to use them to buy the food in Jerusalem - how those coins can be exchanged, a dispute between Beit Shammai vs. Beit Hillel. Plus, the sourcing of the word "money" twice in the biblical verse. Also, when money is an exchange instead of a sale or a purchase payment.

The third perek finished with a discussion about whether intent to misappropriate a deposit is misappropriation. The fourth perek begins with a mishnah discussing how objects are acquired.

2 mishnayot! Additional cases of an object left with a guardian, and how various variables change the guardian's liability. Note the differences between a store keeper, a money changer, and a guardian. Plus, the complications of a change in value and the obligation to replace an unprotected item. Also, when one has to pay the increased value, for wine, for example. Plus, Rabbi Akiva's opinion upheld.

A new mishnah! When a guardian doesn't take good care to protect coins... when is he liable? With a focus on the verses that insist on proper supervision. Also, the blessing that only appears in that which is not obviously visible. Plus, storing money in a place that is protected from one potential threat, but subject to another one. Likewise, the question of whether negligence is relevant when a guardian puts the thing he's protecting under the protection of another. With a slew of cases to explore.

The daf discusses the last mishnah on 40 about whether a barrel being watched may be moved. A disagreement is presented between Rav and Levi if an act is considered misappropriation only if there is actual depletion of the object’s value

Two mishnahs detail how a shomer may deduct from the quantity of produce or liquids left with the shomer when it is returned to the owner.

More on the property of captives. When it's time to harvest from a captives crops, the court appoints a supervisor to take care of that, and then a relative takes care of future planting, and so on. But that kind of administrator would rarely be appointed for an adult. Also, the story of an old woman who has 3 daughters, and she and one of the daughters are taken into captivity. One of the other daughters has died, and left a minor heir. How does the old woman's property get handled? How does an apotropos fit in here, to help the minor?