Complex sentence: Oscar brings the money to the race track to meet Sykes, but becomes distracted by his dreams of grandeur and, upon hearing that the race is rigged, places it all on a long-shot bet by the name of "Lucky Day".
Split into simpler sentences: Oscar brings the money to the race track to meet Sykes, but becomes distracted by his dreams of grandeur. Upon hearing that the race is rigged, places it all on a long-shot bet by the name of "Lucky Day".