This is from thatboardthingee.com
Ricardo stabbed James and ran away. We don't see Ricardo again. I can't really remember the order of events, but Sophie was in Grace's office and in flashbacks we saw her as a teenager. Alan Pierce,Harris and Ricardo beat Valentine while James watched from the doorway. Sophie spat in his face and put the plastic bag over his head to suffocate him. Both Harris and her father, had tried to confess to being the sole killer. Sophie said that Goss figured out that they killed Valentine and Reilly, so they killed him.
With Sophie's help, they figured out James was at the old home. He was still wanted for Alan's murder. While James is slowly bleeding to death, his "innner child" is sitting with him asking whether he was going to get to see his mother. Adult James is trying to read that book he took from Sophie's classroom. Sophie, Boyd and Grace arrive. Sophie cradles James' head as the last bit of life drains from him. James has a brief second of comfort as he looks up at Sophie.