"The pass" is a mountain crossing, so narrow that they's horses done hafta cross it in single file. "Them" (usually rendered as "'em") would be the Bad Guys. What is never made clear is how the Good Guys have a way to get to the pass before the Bad Guys do. However, clearly, once they get to the pass, the Bad Guys could be encircled and trapped by the Good Guys. No oater is complete without a climactic race to "the pass," which the Good Guys win. They then arrest the Bad Guys and read them their Miranda rights. Finally, everyone draws their sixguns at the same time, all the Bad Guys are killed, none of the Good Guys is even nicked, and the ACLU never files a protest.