Dive into the underwater spawning ritual of Trout and related species. The crew's exploration takes them deeper into the northern wilderness along the magnificent Yellowstone River. At LeHardy Rapids, Marty catches slippery Cutthroat to study them face-to-face, then dives into the turbulence to hand-feed a large school of Trout with Salmonfly larvae. Back on the surface, we examine the reproductive cycle and all the other primary predators of the Salmonfly.