JASON HAS A PROBLEM. He doesn’t remember anything before waking up in a bus full of kids on a field trip. Apparently he has a girlfriend named Piper, and his best friend is a guy named Leo. They’re all students at the Wilderness School, a boarding school for “bad kids," as Leo puts it. What did Jason do to end up here? And where is here, exactly? Jason doesn't know anything—except that everything seems very wrong.

PIPER HAS A SECRET. Her father has been missing for three days, ever since she had that terrifying nightmare about his being in trouble. Piper doesn’t understand her dream, or why her boyfriend suddenly doesn’t recognize her. When a freak storm hits during the school trip, unleashing strange creatures and whisking her, Jason, and Leo away to someplace called Camp Half-Blood, she has a feeling she’s going to find out, whether she wants to or not.

LEO HAS A WAY WITH TOOLS. When he sees his cabin at Camp Half-Blood, filled with power tools and machine parts, he feels right at home. But there’s weird stuff, too—like the curse everyone keeps talking about, and some camper who's gone missing. Weirdest of all, his bunkmates insist that each of them—including Leo—is related to a god. Does this have anything to do with Jason's amnesia, or the fact that Leo keeps seeing ghosts?

Join new and old friends from Camp Half-Blood in this thrilling first book in The Heroes of Olympus series. Best-selling author Rick Riordan has pumped up the action, humor, suspense, and mystery in an epic adventure that will leave readers panting for the next installment.

PERCY IS CONFUSED. When he awoke from his long sleep, he didn't know much more than his name. His brain fuzz is lingering, even after the wolf Lupa told him he is a demigod and trained him to fight with the pen/sword in his pocket. Somehow Percy manages to make it to a camp for half-bloods, despite the fact that he has to keep killing monsters along the way. But the camp doesn't ring any bells with him. The only thing he can recall from his past is another name: Annabeth.

HAZEL IS SUPPOSED TO BE DEAD. When she lived before, she didn't do a very good job of it. Sure, she was an obedient daughter, even when her mother was possessed by greed. But that was the problem—when the Voice took over her mother and commanded Hazel to use her "gift" for an evil purpose, Hazel couldn't say no. Now because of her mistake, the future of the world is at risk. Hazel wishes she could ride away from it all on the stallion that appears in her dreams.

FRANK IS A KLUTZ. His grandmother says he is descended from heroes and can be anything he wants to be, but he doesn't see it. He doesn't even know who his father is. He keeps hoping Apollo will claim him, because the only thing he is good at is archery—although not good enough to win camp war games. His bulky physique makes him feel like an ox, especially in front of Hazel, his closest friend at camp. He trusts her completely—enough to share the secret he holds close to his heart.

Beginning at the "other" camp for half-bloods and extending as far as the land beyond the gods, this breathtaking second installment of the Heroes of Olympus series introduces new demigods, revives fearsome monsters, and features other remarkable creatures, all destined to play a part in the Prophesy of Seven.

What dangers do runaway demigods Luke and Thalia face on their way to Camp Half-Blood? Are Percy and Annabeth up to the task of rescuing stolen goods from a fire-breathing giant who doesn't take kindly to intruders? How exactly are Leo, Piper, and Jason supposed to find a runaway table, dodge a band of party-loving Maenads (who just might be a little psychotic), and stave off a massive explosion...all in one hour or less? With his trademark wit and creativity, Rick Riordan answers these questions and more in three never-before-seen short stories that provide vital back-story to the Heroes of Olympus and Percy Jackson books. Original art, enlightening character interviews and profiles, puzzles, and a quiz add to the fun in this action-packed collection.

Annabeth is terrified. Just when she's about to be reunited with Percy—after six months of being apart, thanks to Hera—it looks like Camp Jupiter is preparing for war. As Annabeth and her friends Jason, Piper, and Leo fly in on the Argo II, she can't blame the Roman demigods for thinking the ship is a Greek weapon. With its steaming bronze dragon figurehead, Leo's fantastical creation doesn't appear friendly. Annabeth hopes that the sight of their praetor Jason on deck will reassure the Romans that the visitors from Camp Half-Blood are coming in peace.

And that's only one of her worries. In her pocket, Annabeth carries a gift from her mother that came with an unnerving command: Follow the Mark of Athena. Avenge me. Annabeth already feels weighed down by the prophecy that will send seven demigods on a quest to find—and close—the Doors of Death. What more does Athena want from her?

Annabeth's biggest fear, though, is that Percy might have changed. What if he's now attached to Roman ways? Does he still need his old friends? As the daughter of the goddess of war and wisdom, Annabeth knows she was born to be a leader—but never again does she want to be without Seaweed Brain by her side

Narrated by four different demigods, The Mark of Athena is an unforgettable journey across land and sea to Rome, where important discoveries, surprising sacrifices, and unspeakable horrors await. Climb aboard the Argo II, if you dare. . . .

Hazel stands at a crossroads. She and the remaining crew of the Argo II could return home with the Athena Parthenos statue and try to stop Camp Half-Blood and Camp Jupiter from going to war. Or they could continue their quest to find the House of Hades, where they might be able to open the Doors of Death, rescue their friends Percy and Annabeth from Tartarus, and prevent monsters from being reincarnated in the mortal world. Whichever road they decide to take, they have to hurry, because time is running out. Gaea, the bloodthirsty Earth Mother, has set the date of August 1 for her rise to power.

Annabeth and Percy are overwhelmed. How will the two of them make it through Tartarus? Starving, thirsty, and in pain, they are barely able to stumble on in the dark and poisonous landscape that holds new horrors at every turn. They have no way of locating the Doors of Death. Even if they did, a legion of Gaea's strongest monsters guards the Doors on the Tartarus side. Annabeth and Percy can't exactly launch a frontal assault.

Despite the terrible odds, Hazel, Annabeth, Percy, and the other demigods of the prophecy know that there is only one choice: to attempt the impossible. Not just for themselves, but for everyone they love. Even though love can be the riskiest choice of all.

Join the demigods as they face their biggest challenges yet in The House of Hades, the hair-raising penultimate book in the best-selling Heroes of Olympus series.