She sat right behind a white person and refused to give up her seat to a white passenger who got on after her.
Literal
She [topic-は] white-person's just-after [at-に] sit, her [from-after-の後から] [boarded-and-came-乗ってきた] white passenger [to-に] own seat [object-を] yield [nominalizer-の] [object-を] refused.
A direct reference to Rosa Parks and the 1955 Montgomery bus protest. Several stacked patterns: ~の後 ('after ~,' positionally) here is just-behind in space; ~の後から ('coming from behind ~') in time-and-space; 乗ってきた combines 乗る ('board') with the directional ~てくる ('came having boarded'). 譲る ('yield, hand over') takes に for the recipient. The whole proposition of yielding the seat is nominalized with の and refused.