Final answer:
The characters Sion Fraiser and Johnny Bergoin are likely attempting to intercept or seclude a herd of cattle in a work of fiction, using the geography of the land for strategic advantage.
Step-by-step explanation:
The question posed seems to be referencing a strategy or movement in a fictional context, likely coming from a novel or story which requires understanding literary elements and the plot. Sion Fraiser and Johnny Bergoin appear to be characters possibly working together to isolate a target or to prevent something from joining a larger group or area. Without additional context, it's difficult to provide a direct answer regarding what exactly they are moving to cut off. However, the provided text suggests that they are trying to intercept or seclude a herd of cattle, with the intention of diverting them away from a particular area or to prevent them from being discovered by breaking their line of travel.
This kind of scenario is a common strategic move in storytelling, especially in genres such as Westerns, where protagonists might use the landscape to their advantage to control the movement of animals or to escape pursuit. The reference to 'the sage' implies using tall sagebrush for cover, which further suggests a tactical move being described in the narrative.