Answer: The conflict in chapter 15 of The Lightning Thief is external. Percy, Annabeth, and Grover meet Ares, the god of war, and for a while, he makes them all feel angry and full of conflict. Finally, Ares talks Percy, Annabeth, and Grover into going to Waterland to retrieve Ares's shield. But the quest turns out to be a trap, and Percy, Annabeth, and Grover are almost caught in a magical metallic net made by Hephaestus to catch Ares with his wife. When tiny metallic spiders appear, they are all in danger, and Annabeth especially is creeped out by the spiders. Finally, Percy uses his power over water as a son of Poseidon, making it pour out of the pipes and short circuit the spiders. However, they still need to get out of the place on the Tunnel of Love boat, and just as they think they are close to escaping, they realize that the gates are chained and they will be smashed on them. Using Annabeth's knowledge of physics, she, Percy, and Grover jump out of the ride and to safety. They now know that Ares had more in mind than just asking for their help in getting his shield back, so the conflict is with Ares.