Annabeth wants Percy to go to college with her. So, Percy needed money as well. After being fired from McDonalds because he told an old woman that he wouldn't serve her because she told him his hair looked terrible, he decided to find a job he actually enjoyed. He became a lifeguard at a beach. The employer had hired him as soon as he realized that Percy was a son of Poseidon (the employer was a son of Apollo). Percy could start three days after he applied, and he was the best life guard that the beach ever had.
Yet, the first time he saved someone's life, nobody thought he did anything. A little boy swam to far into the sea, and almost drowned. Percy used his magic to bring him back to the shore. His mother picked up the boy, and after that immediately walked over to Percy. 'Sir, what were you doing? My son almost drowned!' A tear ran down her cheek. 'Sorry, ma'am,' Percy said quietly. He couldn't exactly tell her that he had used magic to bring her son back to the shore. The lady kept screaming at him for another ten minutes, but then Percy saw another person almost drowning. He decided that one lady who was extra mad as him was better than two persons being mad at him, excused himself and ran into the sea. He swam up to the little girl that was almost drowning, and brought her to the shore. Her older brother picked her up and thanked Percy. The later walked back to the lady who had been screaming at him. Her expression was somewhere in between extremely mad and very impressed. She grabbed her sons' hand, and walked away. That day, not much happened at the beach.
The next day, there were a lot of jellyfish at the beach. Not a lot of people showed up because of this, but there was one man who showed up and got stung by a venomous jellyfish. After being at the beach for an hour, he suddenly collapsed. Percy ran over to him, with his phone in his hands. He put his hand on the man's chest, pulling the venom out of his body. He had learned that he should still use mortal ways, so he called an ambulance as wel. It arrived, took the still unconscious man with it and then left again. Percy didn't know what the doctors would think when they realized nothing was wrong, even though he had a bite of a dangerous jellyfish.
Nothing happened for a week, and Percy started to believe that he just had a rough start. Yet, then he saw a hydra walking on the beach. It was luring at little children, and Percy understood that the hydra couldn't have good intentions. He didn't know what the mortals saw, but he did see that people started to back away from it. Percy jumped up and walked up to it. The hydra saw him, and charged towards Percy. Percy uncapped Riptide, and stabbed the thing in the chest. It ran away, of the beach. Everyone went on with their day, but Percy did hear some whispers behind his back. Percy understood - he would have been weirded out if he had seen a life guard attacking a wild 'dog.'