Complex sentence: During one of the Winter Soldier's missions, a brainwashed Black Widow is brought into custody at S.H.I.E.L.D. headquarters; she injures Nick Fury and kills Sitwell before escaping.
Split into simpler sentences: During one of the Winter Soldier's missions, a brainwashed Black Widow is brought into custody at S.H.I.E.L.D. headquarters. She injures Nick Fury and kills Sitwell before escaping.