Yellowstone's spinoff Marshals hinted at Monica's shocking death - but what signs were pointing to Kelsey Asbille's absence? The hit Paramount Network series introduced Us to Kayce (Luke Grimes) and Monica (Asbille), who remained at the center of the show. After initially being a teacher at a local school on the Broken Rock Indian Reservation, Monica went on to become a professor at Montana State University while weathering life with Kayce, who moved them back to the Yellowstone Ranch while figuring out a past divide with dad John (Kevin Costner). Following John's death, Kayce, a former U.S.