When bank robbers and their hostages encounter a backwoods family, they are held captive for a sacrificial ritual, and must work together to escape before becoming human cattle.
For a future logline, you also need to answer the question of then what? What is meant by “human cattle”? Are they a backwards cannibal redneck family? Satanic cult? Been done many times, how is this different? The concept alone of victimizer becoming the victim adds intrigue but further detail will really help sell this.