House of Hades is in excellent sequel to Mark of Athena. It is a fresh face-paced sequel that will keep all Rick Riordan fans satisfied with the humor, action, and drama. The violence isn't very graphic, so there isn't much blood or death. There are a couple kisses between demigods and a mention of someone love for another person who is the same gender. The demigods help each other through battle, and are all positive role models, though sometimes squabbling between one another and mythical figures. Positive messages and learning include the frequent use of Greek and Roman Mythology, teenagers who care for one another and work as a team, and tenderness between girlfriends and boyfriends. Language is kept to a minimum with a few uses of "Gods!" House of Hades is age-appropriate for ages 10 and up, but anyone eleven and up will not be bothered and will enjoy the series just as well. Read this book, but read the rest of the series first. I cannot wait until the next book: Blood of Olympus. Counting down the Minutes!!!!