Percy had to go to the Oracle to see what his quest would be. The Oracle said to travel west, that he wouldn’t rescue what matters most, and a friend would betray him. After he visits the Oracle he starts his quest with Annabeth and Grover.
Ares visited Percy telling him he needs a favor and in return the three of them get a ride west. Percy was heavily disrespecting Ares which had made Ares mad. His eyes were filled with flames. In Ares’ presence Percy was filled with anger.
The three of them were exhausted from traveling in the back of a steamy truck and was walking around Las Vegas when they found Lotus Hotel. They were living in luxury there. They thought they were only there for a couple hours but it had been days before they escaped.