Complex sentence: He tracks down an old high school friend, Ben, whom he to lend him a rifle before traveling to a field to negotiate with Teddy, in a bid to guarantee that the Clelands leave his sister alone.
Split into simpler sentences: He tracks down an old high school friend, Ben, and asks him for a favor. He persuades Ben to lend him a rifle before traveling to a field to negotiate with Teddy, in a bid to guarantee that the Clelands leave his sister alone.