“The House of Hades” is a book written by Rick Riordan. It is the fourth book in the series “Heroes of Olympus.” It is about Greek and Roman mythology. The book follows the seven prophecies and their companions on their quest to close the Doors of Death, stop the Giants from raising Gaea, and prevent war between Camp Jupiter and Camp Half-Blood. This isn’t an easy task, and the protagonists run into many foes along the way to completing their quest. The protagonists have to overcome many obstacles and defeat many of Gaea’s children along the way. In this book the main protagonist characters are the seven prophecies and a few other characters. Their names are the following: Percy Jackson, Annabeth Chase, Leo Valdez, Hazel Levesque, Frank Zhang, Piper McLean, Jason Grace, Nico Di Angelo, Reyna Avila Ramírez-Arellano, Coach Hedge, Damensen, Bob the Titan, and the gods of Olympus. The main antagonists are Gaea, her children, and Tarturus. The novel has many settings. The most important settings are the Doors of Death (on both sides), Tartarus, and Calypso’s island. The Doors of Death are the main setting in this book because of its impact on the whole story. In the series Heroes of Olympus, the seven prophecies have to defeat Gaea and close the Doors of Death. This shows how the doors of death are a very important thing in the book and even the series. The setting takes place near the very end of the book. In the mortal world, the Doors of Death are located in the House of Hades. It is a very dark and deep intricate maze of corridors which are very hard to navigate. The characters in this story are able to navigate the corridors with Hazel Levesque. She is a child of Pluto (Hades Roman form) and is an underground expert. It is very dark and gloomy in the House of Hades. These seven prophets meet many of Gaea’s monster children, like earthborn, gryphon, cyclopes, and many more. They also encounter the two gods guarding the doors of death. Their names are Clytius and Pasiphaë. Clytius is a dark powerful being who can suck in people’s life force. He is immune to almost anything except fire, though it has to be very powerful fire. On the other hand, Pasiphaë is a sorcerer and is a master with the Mist. She also is well-known for giving birth to the Minotaur. The Doors of Death from what Percy and Annabeth thought was the opposite of the doors of the elevator to go to Mount Olympus. Mount Olympus’ doors were white, while the Doors of Death had the same design but were black. Percy describes the Doors of Death, “A freestanding rectangle of darkness (Riordan 461-462).” and “Framed in Stygian iron, the magical portal was a set of elevator doors–two panels of silver and black etched with art deco designs. Except for the fact that the colors were inverted, they looked exactly like the elevators in the Empire State Building, the entrance to Olympus (Riordan 463).” Percy sees the Doors of Death and relates them to the doors to Olympus. Percy describes the Doors of Death as the same design as the doors to Olympus, but inverted. This shows how the doors to Olmypus are white which symbolizes good, and the Doors of Death are black which symbolizes evil. When Percy sees the Doors of Death, he gets homesick when he sees them because it reminds him of New York, Camp-Half Blood, and his mom and stepdad. This further shows how the Doors of Death are the opposite version of the doors to Olympus. Gaea and her children also chained up the Doors of Death so it could not relocate. The next setting in “The House of Hades” is Tartarus. This is where Percy and Annabeth went when they fell into the cavern of Arachne, A.K.A the Weaver. Percy, Annabeth, and Bob the Titan, travel through Tartarus to get to the Doors of Death to escape and stop Gaea’s plans. They encounter many monsters and gods that are on Gaea’s side, and one that is friendly to them. The friendly one being Damensen, the giant who is the anti-Ares. He is nice because Ares is not a nice person and the opposite of Ares is nice. That made Damensen nice. The monsters and gods they encounter are Nyx and her children, Hyperion, Krios, Kelli, and many more. The final important setting in “The House of Hades” is Calypso’s island. This is a very important setting because Leo changes very much. He is a little less joking and becomes more caring. He also swears on the River Styx that he will break Calypso’s curse and get her off her island. I also think that Leo will get Calypso after the seven defeats Gaea in the fifth book in the series. This setting causes a major character arc for Leo Valdez. Leo is also able to make a fireproof drawstring bag for Frank Zhang’s piece of firewood that is connected to his life. Because of the drawstring bag, Frank Zhang also had a major character arc. Frank became more confident and less worried about his weakness of fire. I really like this book because it has many plot twists and is very enjoyable to read. I would recommend this book to the people who liked the Percy Jackson Series/Heroes of Olympus Series. I would rate this book a 10/10.