Reyna took off without second thought, her slim body swaying as she sprinted down the street. Coach started after her, but Nico held up his arm, stopping him in his tracks.
"You need to stay here, to guard the Parthenos." He nodded at the statue.
"Aw, come on! All I do is sit and guard!" Coach protested.
"You have to. Just until Reyna and I come back. Don't let it out of your sight."
With that, Nico rushed down the sidewalk, pushing past citizens and winding around streets. He caught a glimpse of Reyna around the corner of a building, running like a mountain lion, her sword gripped firmly in her hand. Nico unsheathed his own Stygian iron sword, the metal glinting black in the sunlight. He pumped his legs as quickly as he could, struggling to catch up with Reyna, his pulse thumping in his ears, until they rounded another corner into a children's playground. There, crushing a swing-set under its weight, was a Hydra–and by far the largest one Nico had ever spotted. About the size of an elephant, with a plump body cloaked in gray-tan scales, and on top of that, four hissing heads with forked tongues and beady black eyes.
The kids around the monster screamed, running away in laughter as if it was a game of tag. The Hydra roared–a horrible mucus-filled gurgling that sent tremors through the ground–and staggered forward, toward the children.
"Hey!" Reyna called, holding two fingers to her lips and whistling. The Hydra whipped around, fixing the eyes devoid of light on her and Nico, its green lips curling into a snarl. The creature opened its jaws, breathing outward, sending a plume of hot-red fire coiling toward them. Nico instinctively fell to the earth, the air boiling above him, his eyes squeezed shut and breath held as sweat formed on his forehead. Once the heat died down, he pushed himself to his feet, opening his eyes and glancing around. Reyna stood a couple feet away, the tips of her bangs singed off, the skin of her nose a light pink. Around them, the playground was in flames, the monkey bars charred and wooden playhouse reduced to ashes. A ring of fire encircled them, forming a barrier between them, the beast, and the kids, who were shrieking playfully outside the destruction.
Nico's sword felt hot in his hand. He tightened his grip on the leather handle, meeting Reyna's eyes, a silent agreement passing through as she shook her head slightly. Not yet.
The Hydra growled and paced, as if impatient. Nico knelt down, cautiously taking a burnt rock in his fingertips, the heat pricking his skin. He reeled his arm back, careful not to draw attention, and in one, swift motion, stepped forward and released. The stone sailed through the air, smacking the Hydra's left eye, sending it stumbling backward, roaring in outrage, smoke hissing from its flared nostrils.
Now.
Nico charged, raising his sword and shouting Ancient Greek curses. Reyna did the same, her mouth open in a snarl, brown hair flying in a tangled mess behind her. Together, they attacked, Nico slicing at the Hydra's fat belly while Reyna jabbed at its back. The monster flailed, whipping its heads around furiously, venom dripping from the four pairs of fangs. Unfortunately, their assault seemed to only aggravate the thing–and once it stopped jolting back and forth, it lowered two of the heads and swung, one of them hitting Nico square in the chest, sending him tumbling backwards. The second slammed into Reyna, knocking her off her feet and rolling into the remnants of a slide. Nico looked up, his mind fuzzy, just as another volley of fire was launched, nearly turning him into a barbecued son of Hades. He ducked just before the flames reached him; never had he more wished to have Leo Valdez here, with his fire immunity and endless toolkit.
As he opened his eyes, his vision blurry from the heat, he spotted Reyna struggling to get to her feet, her eyes sizzling with anger. She raised her sword, charging the monster, her teeth gritted and eyes narrowed in furious determination.
Nico realized a little too late–Reyna had never fought a Hydra before.
"Wait!" he yelled, just as her sword sliced through the thickness of a single neck. The head fell, fangs and all, face frozen in a snarl. Green ooze dripped from the stub, forming a pool of slime around Reyna's feet. She grinned and looked up at Nico, her cheeks smeared with ash.
"How's that?" she called. Nico shook his head in response, his eyes fixed on the stub, the ooze mutating into a ball. His jaw fell as a head was formed, then split into two, five heads in total now glaring at them with even beadier eyes. Reyna's grin faltered as the Hydra hissed behind her, yellow fangs glinting in the firelight.
"When you cut a Hydra head off, two more grow in its place," Nico explained as Reyna turned, slack-jawed and wide-eyed, her grip on her weapon loosening. Something about her expression made Nico's skin crawl–her dark eyes shone with fear as she glanced around hopelessly, like a lost puppy. For once, the great Reyna, praetor of New Rome, didn't have a plan. She had no idea how to defeat this monster.
But she caught herself in an instant, and the glimpse of weakness was gone.
"Well, how do we kill it, then?" she demanded, her lips pursed and sword lifted. Nico considered this, the Hydra letting out another impatient growl.
"Fire. If we catch some of it, we can use it to burn the stubs. Then the heads won't grow back."
"And how are we supposed to catch fire?" The Hydra crouched down as if preparing to pounce, a plume of smoke spiraling from its nostrils.
"You figure that out. I'll distract it."
Without hesitation, Nico surged forward, his fingers wrapped firmly around the hilt of his sword. The Hydra moved, staggering on its large feet, snapping at Nico as he ran. He pumped his legs as quickly as he could, then jumped, leaping onto the beast's leathery back. The Hydra shrieked–a horrible bird-like noise–and bucked, rocking back and forth like an angry bull. Nico grabbed onto the dry, scaly skin, digging his fingernails into the spine as the creature flailed, threatening to rocketing him into orbit. He released one hand, nearly losing his grip, to raise his blade and sink it into the fiend's flesh. The Hydra screeched and lurched forward, Nico's hand ripped from its hold, sending him flying through the smoky sky. He landed on the stone pavement, hard, pain boiling in his spine.
Nico let out an involuntary cry, grinding his teeth, then turned on his side, squinting his eyes to see through the haze. He could just barely make out the silhouette of Reyna, her own blade slicing through two heads with ease.
He pressed his palms to the ground, struggling to stand, nausea sweeping through him when he got to his feet. Red tinged his vision as he stumbled forward, tripping over his own shoes. The image of the battle cleared through the smoke–Reyna and the Hydra locked in combat, green ooze gushing from various wounds in the monster, fire being launched and swords swung. Just as Nico took his weapon in hand, the Stygian iron blade chipped, another set of flames was sent flying, aimed directly at Reyna's face. But this time, Reyna raised something–a large slab of splintered wood, probably from disembodied play structure. Immediately the wood caught fire, missing Reyna by a centimeter, and she chucked it at the four neck stubs. They went up in flames, the Hydra's entire body crumpling, one remaining head spitting venom as it went down.
As the monster transformed into dust and dissipated into the wind, Nico un-tensed, inhaling the toxic air–then doubled over in a coughing fit, bringing his hand to his mouth as he hacked, his lungs withered like dead flowers. When he straightened, Reyna was at his side, her hand on his shoulder.
"You okay?" she asked, her voice hoarse. Nico weakly swatted her hand away.
"I'm fine," he croaked. "What about you?"
The tips of her hair were singed, as well as the cuffs of her jeans and sleeves of her shirt. Ash and dirt caked her from head-to-toe, and exhaustion was plain on her face. Nico's own eyelids were a little heavy.
"I'm all right. Another monster defeated. More mortals saved."
"Hm. Well, good job, I guess. With the fire and all," Nico said half-heartedly, sheathing his sword.
"Thanks. I, uh, I couldn't have done it without you."
He stopped moving, looking at Reyna, dusting herself off casually. No one had ever complimented him before. Maybe it wasn't a compliment, maybe it was only politeness–but it was something. And gazing at Reyna, frowning at her charred boots as if what she said was no big deal, somehow made his heart light.
But she cleared her throat, and he forced himself to look away.
"I suppose we should go. Get back to Hedge, make sure the Parthenos is fine..."
"Yeah, yeah. Let's go."
They cleared a path through the fire. All the mortal children had cleared, hopefully escaping the playground and returning to their parents, leaving a deserted street and a burnt-to-a-crisp park. The city was an eerie type of peace, but Nico enjoyed it nonetheless, appreciating the quiet.
They had just rounded a corner, Coach Hedge and the Athena Parthenos coming into view, when something slammed into Nico's temple, and the world went black.