Complex sentence: Kirk offers Nero help to escape, but Nero refuses, prompting Kirk to give the order to fire, dooming the "Narada" to be consumed in a black hole.
Split into simpler sentences: Kirk offers Nero help to escape, but Nero refuses, prompting Kirk to give the order to fire. As a result, the "Enterprise" fires on the "Narada", dooming the "Narada" to be consumed in a black hole.