Question: percy jackson book after the son of neptune
[{'answer': 'The Mark of Athena', 'provenance': [{'wikipedia_id': '28056365', 'title': 'The Heroes of Olympus', 'start_paragraph_id': 15, 'start_character': 11, 'end_paragraph_id': 15, 'end_character': 29, 'bleu_score': 1.0, 'section': 'Section::::Books.:The Son of Neptune.\n'}]}]