Charleston is a city on the Eastern Coast of South Carolina, USA. It is famous for Fort Sumter, the area where the first shots of the American Civil War were fired. Charleston is known as The Holy City. Charleston's name is derived from Charles Towne, named after King Charles II of England.
The city of Charleston is first mentioned by the sea god Phorcys when he tells Frank Zhang and Percy Jackson that a map to the Mark of Athena is located there. The seven demigods are forced to take the long way to Charleston after being tailed by Roman demigods. Jason Grace states he knows of two places where the map may be and offers to lead Leo Valdez and Frank to a museum he had previously visited with Reyna. Annabeth Chase then travels with Hazel Levesque and Piper McLean to a park where Jason says there is a ghost, who will only talk to female demigods, while Percy decides to talk to the water nymphs in the area.
Upon reaching the park, Hazel declares that the ghost is fake and Piper reluctantly states that it is her mother, Aphrodite. During the goddess' tea party, she explains, along with a few fashion tips, that the Mark of Athena selects a few children of Athena each generation to find Athena Parthenos and sends them on their way to Fort Sumter, where the map is located.
As they make their way to the Argo II, Annabeth, Piper, and Hazel are surrounded by Octavian and two other Roman commandos. Annabeth throws her dagger into the water which summons Percy to come and rescue them, whilst leaving the Roman demigods floating in the sea. The four demigods board the Argo II and fly toward the fort, contacting the others along the way. Jason and Frank, who has transformed into a giant bald eagle and holding Leo in his claws, fly toward the ship, but are forced to overtake the ship when they are attacked by more Romans and crash land in Fort Sumter. Annabeth tells Piper, Hazel, Percy, and Gleeson Hedge to protect the ship while she finds the others. She locates Jason and tells him to retreat while she searches for the map. Annabeth, however, is trapped in a room filled with spiders while Gaea mocks her. The Mark of Athena burns the spiders to a crisp just like in the demigod's nightmares and leads her toward the map. Upon finding the map, Annabeth is confronted by Reyna, who tells her that if she and the others do not surrender, the Romans will attack Camp Half-Blood. Horrified, Annabeth declines, and Reyna tells her the next time they meet, they will be enemies.
Annabeth rushes back to the ship as more Romans attack, but is pulled on deck by Piper. Jason and Percy create a huge storm that speeds the Argo II on its way.
- The capital of West Virginia is also named Charleston.