If a Jew leaves wine with a non-Jew, unsupervised, can (or when can) the Jew drink that wine? The 12 case-stories on this daf address this question, several of which are discussed here. Also, when an army came to Nehardea and opened barrels of wine - is that wine permitted for the Jews to use? A comparable question arose in the land of Israel, but it's also qualitatively different, when the army is primarily Jewish. Plus, the case of a Jewish woman who gives the key to her wine shop to a non-Jewish woman, as an indicator of trust between them.