All the evidence that could have exonerated her father was on that plane that exploded

Not exactly. Nolan backed up the mysterious hard drive before he gave it to the SEC guy. He lets Emily know that Americon handled the cover-up after the Graysons framed her father. An old videotaped conversation between Victoria, Conrad and the white-haired man completely floors Emily. She learns that her thought-to-be-dead mother may actually be alive.