River Jackson is the younger sister of Percy Jackson. She adores her older brother, but when she's revealed to be the daughter of Neptune, a voice tells her to leave and never go back. But when her brother goes missing and ends up at Camp Jupiter, she knows she can't sit back and hide anymore. One slight problem; her father, Neptune, summons her to his palace in order to prepare for the prophecy of the seven and the battle with Gaea. When she meets the seven on the Argo II, she's different. What Neptune put her through may have broken her.... and when it comes down to sacrifice her life for the ones she loves, will she do it?