Complex sentence: Scratcher, taking adventage of Rudolph's kindness, steals money from the circus and set up Rudolph to take the blame after making a deal with Winterbolt, who extended the powers of the amulets Frosty's family wears for an infinite time in exchange.
Split into simpler sentences: Scratcher, taking advantage of Rudolph's kindness, steals money from the circus and sets up Rudolph to take the blame. Rudolph agrees to appear guilty after making a deal with Winterbolt, to extend the powers of the amulets Frosty's family wears for an infinite time in exchange.