Complex sentence: He recruits the Maximoff twins, who harbor a grudge against Stark for weapons responsible for their parents' deaths, and together, they visit the base of arms dealer Ulysses Klaue in a shipyard near Johannesburg to obtain vibranium.
Split into simpler sentences: He recruits the Maximoff twins, who want revenge against Stark for their parents'deaths from his company's weapons. Together, they visit the base of arms dealer Ulysses Klaue in an African shipyard to obtain vibranium.