During the trip, Hazel gives Percy a sisterly kiss on the cheek. After being assaulted by gryphons, they remain at Hazel's old house for a bit before transporting Arion to the home of the giant Alcyoneus, who imprisoned Thanatos. She also expresses her affections for Frank and kisses him to demonstrate her affection. In Book Four, Chapter Nine, we see that she has fallen in love with Frank. She tells him so when he asks if she is still in love with Lucius. Lucius had used his magick to turn Hazel into a horse so he could use her as a mount. When she becomes angry instead of afraid, he takes advantage of this and makes her his own personal horse. He uses her to travel around Greece looking for Titan, the man who had captured Persephone. During the search, Hazel helps free Zeus from captivity and reunites him with Persephone. Once everything is back to normal, Hazel and Frank return home. In Book Five, Chapter One, we find out that Hazel and Frank are going to be married after all this time. Before they get married, however, Frank's father, Charon, dies. This causes a large argument between Hazel and Charon because he wanted her to take care of himself now that he was dead. However, she decides to go ahead with the wedding anyway.