Let's address what happens to Percy and Annabeth at the Casino in the *Percy Jackson & the Olympians* series:
* The Casino scene you're probably thinking of is in the *The Lightning Thief*, the first book. However, Percy and Annabeth are not together at the casino.
Here's what happens to each of them:
* Percy: He arrives at the casino in Las Vegas with his mom and her boyfriend, Gabe. While trying to avoid Gabe's attempts to use his credit cards, Percy witnesses Gabe stealing money and is pursued by casino security. This encounter leads to Percy discovering his powers and ultimately running away from the casino.
* Annabeth: Annabeth, a demigod daughter of Athena, is tasked with finding Percy and bringing him safely back to Camp Half-Blood. She doesn't appear in the casino scenes, but she is tracking Percy's movements.
While neither Percy nor Annabeth interact at the casino, their paths ultimately converge as Annabeth tracks Percy down and helps him escape the casino and the pursuing monsters.
Let me know if you'd like to know more about the Casino scene or any other part of *The Lightning Thief*!