The House of Hades (Heroes of Olympus Book 4)

Hazel’s skin tingled coolly, as if she’d been rubbed with alcohol. In front of her, an arched gateway led through mossy walls into some sort of enclosure.
    Hazel couldn’t see much through the gloom, but she felt a presence within, as if she were a chunk of iron close to a large magnet. Its pull was irresistible, dragging her forward.
    Yet she hesitated. She reined in Arion, and he cloppedimpatiently, the ground crackling under his hooves. Wherever he stepped, the grass, dirt and stones turned white like frost. Hazel remembered the Hubbard Glacier in Alaska – how the surface had cracked under their feet. She remembered the floor of that horrible cavern in Rome crumbling to dust, plunging Percy and Annabeth into Tartarus.
    She hoped this black-and-white hilltop wouldn’t dissolve under her, but she decided it was best to keep moving.
    ‘Let’s go, then, boy.’ Her voice sounded muffled, as if she were speaking into a pillow.
    Arion trotted through the stone archway. Ruined walls bordered a square courtyard about the size of a tennis court. Three other gateways, one in the middle of each wall, led north, east and west. In the centre of the yard, two cobblestone paths intersected, making a cross. Mist hung in the air – hazy shreds of white that coiled and undulated as if they were alive.
    Not mist, Hazel realized.
The Mist.
    All her life, she’d heard about the Mist – the supernatural veil that obscured the world of myth from the sight of mortals. It could deceive humans, even demigods, into seeing monsters as harmless animals, or gods as regular people.
    Hazel had never thought of it as actual smoke, but as she watched it curling around Arion’s legs, floating through the broken arches of the ruined courtyard, the hairs stood up on her arms. Somehow she knew: this white stuff was pure magic.
    In the distance, a dog howled. Arion wasn’t usually scared of anything, but he reared, huffing nervously.
    ‘It’s okay.’ Hazel stroked his neck. ‘We’re in this together. I’m going to get down, all right?’
    She slid off Arion’s back. Instantly he turned and ran.
    ‘Arion, wai–’
    But he’d already disappeared the way he’d come.
    So much for being in this together.
    Another howl cut through the air – closer this time.
    Hazel stepped towards the centre of the courtyard. The Mist clung to her like freezer fog.
    ‘Hello?’ she called.
    ‘Hello,’ a voice answered.
    The pale figure of a woman appeared at the northern gateway. No, wait … she stood at the eastern entrance. No, the western.
Three
smoky images of the same woman moved in unison towards the centre of the ruins. Her form was blurred, made from Mist, and she was trailed by two smaller wisps of smoke, darting at her heels like animals. Some sort of pets?
    She reached the centre of the courtyard and her three forms merged into one. She solidified into a young woman in a dark sleeveless gown. Her golden hair was gathered into a high-set ponytail, Ancient Greek style. Her dress was so silky it seemed to ripple, as if the cloth were ink spilling off her shoulders. She looked no more than twenty, but Hazel knew that meant nothing.
    ‘Hazel Levesque,’ said the woman.
    She was beautiful, but deathly pale. Once, back in New Orleans, Hazel had been forced to attend a wake for a dead classmate. She remembered the lifeless body of the young girlin the open casket. Her face had been made up prettily, as if she were resting, which Hazel had found terrifying.
    This woman reminded Hazel of that girl – except the woman’s eyes were open and completely black. When she tilted her head, she seemed to break into three different people again … misty after-images blurring together, like a photograph of someone moving too fast to capture.
    ‘Who are you?’ Hazel’s fingers twitched at the hilt of her sword. ‘I mean … which goddess?’
    Hazel was sure of that much. This woman radiated power. Everything around them – the swirling Mist, the monochromatic storm, the eerie glow of the ruins – was because of her presence.
    ‘Ah.’ The woman nodded. ‘Let me give you some light.’
    She raised her hands. Suddenly she was holding two old-fashioned reed torches, guttering with fire. The Mist receded to the edges of the courtyard. At the woman’s sandalled feet, the two wispy animals took on solid form. One was a black Labrador retriever. The other was a long, grey furry rodent with a white mask around its face. A weasel, maybe?
    The