Complex sentence: Kirk and the others free the crew as Krall launches from his camp with the bioweapon and leads his fleet to "Yorktown", and the "Enterprise" crew pursues Krall in the "Franklin".
Split into simpler sentences: Kirk and the others free the crew as Krall launches from his camp with the bioweapon and leads his fleet to "Yorktown". The "Enterprise" crew pursues Krall in the "Franklin".