Complex sentence: Shields gets into a high-stakes poker game with Pebbel and loses a lot of money to him so that he can talk Pebbel into letting him work off the debt by making low-budget films for him.
Split into simpler sentences: Shields gets into a high-stakes poker game with Pebbel. He intentionally loses a lot of money to him so that he can talk Pebbel into letting him work off the debt by making low-budget films for him.