What is the main conflict in Summer of the Monkeys by Wilson Rawls?

One day, a circus train derails near the Lee farm; one car bursts open allowing twenty-nine circus monkeys to escape. The circus offers a huge reward for the capture and return of the monkeys. Jay Berry, with his trusty hound dog Rowdy, discovers the monkeys have taken up residence on the family farmland in an overgrown area called the river bottoms. Jay Berry consults with his canny grandpa and they attempt to catch the monkeys.