Complex sentence: Agents of the Third Reich, however, make an appearance, killing Hayes and making off with the artifact, forcing Fenton to follow them back to Berlin, in which the city is in the process of hosting the the 1936 Olympic Games.
Split into simpler sentences: Agents of the Third Reich, however, make an appearance, killing him and taking the artifact with them. Fenton follows them back to Berlin, where the city is in the process of hosting the the 1936 Olympic Games.