Complex sentence: After some prompting by Luke, Jace returns to the institute to confront Alec's and Izzy's mother who had kicked him out, upon his arrival she reveals that the inquisitor was coming and she was only trying to spare him.
Split into simpler sentences: After some prompting by Luke, Jace returns to the institute to confront Alec and Izzy's mother who had kicked him out. She then reveals that the inquisitor was coming and she was only trying to spare him.