-Percy-

I wish I could say that we escaped the Danaids, and we made it to the doors no problem.

That would have been a big fat lie.

We ran flat out for what felt like a whole day. We would all stop to catch our breath, and right when we would get it, another monster would come around the corner. The rage of the Danaids had alerted Hyperion and Krios's army to our presence. Thanks to Addie, we had managed to stay ahead of them, but just barely. Annabeth and I had both sustained some injuries, minor cuts and bruises, but nothing that we were not used to. We had killed some monsters, but for the most part, Addie took care of everything and anything that came into our path.

I do not know what was in that potion she took, but whatever it was, she appeared to feel a lot better, at least for a little while. She took down monsters without any hesitation, her daggers whirling around her. Every single move was graceful, like a panther or tiger waiting to strike. The earth slid around her like it was following her lead. A rock would fly right where she needed it, or she would get a boost at the exact right moment. She reminded me of the ultimate war machine; she was smart, fast, and deadly. I had never seen anyone except a god fight as well as she did, and I bet that she could have taken most of them.

They could strike me down if they wanted to. I was just being honest- Addie was that good.

We had just made it around the corner, and we paused to catch our breath once again. It seemed we had outrun them for a few precious minutes. Addie put her hand on the wall, and she looked content.

"We are ahead for now, but we will have to keep moving to stay that way," she said as she leaned back against the rock wall. Addie reached into her bag, pulling out a small green vile.

"Catch!"

She tossed it towards Annabeth, who caught it nimbly. She looked at Addie questioningly, and before I could ask her what it was, she made a motion with her hand.

"Drink it, split it between the two of you. It's an energy potion," she explained. Annabeth uncorked it, taking a deep swig. She handed it to me, and I chugged the rest of it down. It tasted like a mixture of nectar and espresso, which actually was not nearly as bad as it sounds. It was actually really good. Energy thrummed in my veins. It was like I had slept a good twelve hours, and then had a cup of coffee on top of that.

I saw Addie reach into her bag, and she pulled out the golden vile of nectar Apollo had given her. She took the stopper off, and I noticed her hands were shaking. In fact, her whole body was shaking. She took a quick swig and then sighed deeply. The slight sheen of sweat was starting to come back and light grey circles were beginning to form underneath her eyes. We had been running off and on for hours now, and I was surprised she did not look worse. She stopped shaking as the nectar started to take effect, and she stuck the vile back in her bag.

"What was in that potion Phoebe gave you?" I asked.

"We need to keep moving," she said, starting down the tunnel again. We both followed her, our quick footsteps crunching against the rock.

"Addie-" Annabeth started.

"I'm fine. Just a potion to buy me some time, that's all. I just want to make sure I can make it to the doors."

"How much nectar do you have left?" Annabeth said worriedly.

"I'll be fine," she assured us. Annabeth glanced at me, concern in her eyes. If Addie crashed from this potion, how would she survive?

"Addie," I started to say.

"Yes?" she replied, a little out of breath. She was struggling to catch her breath this time. It sounded more ragged, but she managed to put a small smile on her face.

"Don't blow yourself out. Don't do too much. Please."

She slowed down for a minute and then stopped completely. She turned to look at me, sadness in her gaze.

"I'll try, Percy. I promise."

I nodded my head, and Annabeth took my hand.

We came into a cavern, the lava river roaring around us. The heat was almost unbearable, but thanks to Addie, we were not getting burned.

"What are we looking for?" Annabeth asked.

"A corridor, one that leads off to another cavern. Thantos said the doors would be in there, or at least that is where he said he thought they were. I assume he was right because the army is following us. Plus, we are in the heart; we should be very close. This is where the Phlegethon begins."

We walked into the cavern, and I searched for the corridor she had mentioned.

"Is that it?"

Across the river, about twenty feet above us, was an archway, leading into a dark black tunnel. There was a worn footpath that snaked up the ledge, leading to the archway.

"That would be it," she agreed.

The only problem was that it was on the other side of the Phlegethon.

"How are we going to get across?"

"Rock Bridge," Addie said.

Addie looked to the huge rock that was beside us, and a large rectangle cut itself out of the wall. She moved it so it spanned the river. It stuck out about ten feet on each side of the ledge of the riverbank, the molten lava beating hard against the bottom.

"You two go ahead. I'll make sure it does not move, and I will be right behind you."

We started up it. Annabeth led the way, her hand in my own. The rock was vibrating with the force of the river, and I was glad I had Annabeth's hand to help keep my balance. Now I understood why Chiron always said that balance was a hero's best friend.

We made it to the other side, and we both jumped down. I looked back at Addie, who was leaning against a rock, her eyes on us. Terror rocked through my body, and I felt my battle adrenaline kick in.

Hyperion and Krios's army had caught up.

"ADDIE! BEHIND YOU!"

She turned quickly, and I could see her body tense up.

"Go! Get to the Doors! I'll be right behind you!"

Hyperion had stepped forward, his gold glow emanating from him. Addie looked just as formidable, a fierce look on her face.

She launched herself at him, and I moved towards her. I had to help. Something grabbed my arm, hauling me in the opposite direction.

"Come on, Seaweed Brain! You heard her!"

Annabeth and I ran up the path, dodging arrows and fire blasts. We made it inside the tunnel, and I turned around, my eyes looking around wildly.

"Where's Addie!?" I asked shrilly.

"Right here," came Annabeth's voice.

Addie grabbed each of our arms, dragging us further into the cavern. She turned, and with a flick of her hand, sealed up the opening behind us.

"That will keep them from coming in, but not for long," she said gasping.

She looked past us, and awe crept on her face. In front of us were two black doors, dark as the night sky. The cavern was filled with red light, from pools of lava that were bubbling up. The doors were tall, around twenty feet or so, and there was an inscription on them, written in pale silver. The seemed to glow against the wood, like stars in the night sky.

It read: θάνατος οὐδὲν διαφέρει τοῦ ζῆν.

"Thánatos oudèn diaphérei tou zên," Addie whispered. I knew it was Greek, but my mind was racing so fast, I could not put it to the proper words.

"Death is no different than life," Annabeth translated.

The doors were being propped open by a sinister-looking black vapor, sort of like a chain. There was nothing on the other side except a profound emptiness. It was the same shade as the doors, and it looked to me like the pit looked before we fell. Addie walked up and placed her hands on the edge of the door. The scene shifted, and it came to rest on a black obsidian building. I ran to the edge, looking at the scene in front of me.

A battle was raging. Jason, Piper, Leo, Frank, and Hazel were all fighting fiercely against a horde of monsters. The Argo II could be seen in between the columns. Coach Hedge was flying around the building, yelling "Die, Monster Scum, Die!"

"Go, help your friends, they need you. I'll stay and shut the doors. I'll just need help from your side," Addie said thickly. I looked at her. A single tear was running down Addie's cheek, but I could tell a lot more were threatening. Annabeth embraced her, wrapping her arms around Addie. Addie hugged her back.

"We can't just leave you," Annabeth said tearfully. I felt like there was a rock in my chest and a lump the size of a bowling ball in my throat. Addie broke away, looking at Annabeth lovingly like she was looking at her sister.

"Yes, you can," she said firmly. "Go kick Gaia's butt, save the world. Here." She took off her bag and put it around Annabeth's body. It hung across her torso, like a messenger bag. Annabeth's eyes were filled with tears, one finally spilling down her cheek.

"I-I can't take this."

"I won't need it down here, Annabeth," Addie told her gently. "Keep it safe for me."

Addie turned towards me, and for a second we just stared at each other. I could hear the other's battle from the other side of the doors. I could hear something hitting the rock wall that separated us from Hyperion and Krios's army. The world seemed to slow down, and I wanted to scream.

This was not fair, not even close.

"I'll stay behind," I told her firmly. Addie shook her head, taking a step towards me. A rumble shook our little cavern, and Addie looked apprehensively at the barrier she had created.

"They need you, Percy. They need you both. This is your fight. I've done my part."

I stepped quickly to her, pulling her into my arms. This was the first time I had ever hugged my sister, and it would possibly be the last time I ever saw her.

Another rumble shook through the cave, and some of the rocks fell from the wall that had closed the archway.

We broke apart, and she scrambled for the necklace around her neck.

"You need to go, you need to go now! Take this and give it back to Apollo," she said shoving it into my hands. I put it in my pocket and grabbed Riptide. "Tell him I am sorry, and that I will try my best." The tears were falling freely down her face now, but she never let out a sob. "Annabeth, you will have to cover for him while he helps me shut these doors. As soon as they shut, I'll say the words, and hopefully, they will disappear."

Annabeth nodded her head and pressed a small gold vile into Addie's hand. Addie stared at it, and then slid it into her pocket.

"Fight hard, Addie. We will get you out of here," she said confidently. She looked in my direction and nodded. She was telling me to hurry, and she was giving me a chance to say goodbye to my sister alone. Annabeth stepping through the portal, and it shimmered, like water off the bay in the summer.

I did not know how I felt. I know I felt empty like there was a black hole in my chest. I reached for Addie, my mouth open to tell her something, what I was not sure.

A huge chunk of rock fell from the wall, revealing a tiny hole. A golden hand poked through the wall, ripping the rock away handful by handful.

"Gods, Percy, go!" she shouted at me. She shoved me out the door. I could feel the ground shifting underneath my feet, pulling me away from her and the door. My hands gripped the edge. It was open just enough that I could touch both sides. I was halfway in Tartarus, halfway in the real world. Addie placed her hands over mine, and she began to slide them shut. I could see the strain it was causing her, the amount of energy and power she had to put into it.

And I could not help her. The panic and despair finally broke through.

Please… someone, anyone. Help us. I prayed silently. I did not know which god I was talking to. I did not know if they were watching, or if they could even see Addie. Dad, please, not her! This is not fair! I finally found my voice, and I could hear the panic in it.

"I'm not leaving you in Tartarus to die! There's got to be another way-"

"There is no other way, Percy! DUCK!"

I bent down, and she slashed above me with one of her daggers. A draconae disintegrated behind me. She grabbed each of the doors and began to push them closed once again. I pulled from my side. I knew Annabeth was behind me, keeping the monsters off my back. We had closed the doors almost all the way now. There was a slim opening, just enough for a single person to squeeze through sideways.

"Percy, Annabeth!"

Frank was behind me, fighting off Gaia's horde. I looked behind me for just a second, and I saw Jason come to Annabeth's side, helping her defend me. My hands were keeping the doors open now, Addie's face just inches from my own.

"I'm not leaving you in here," I whispered to her. Somehow over the roars, it was remarkably quiet. It was like we were in a bubble and time had slowed down. Maybe it really had. She placed one of her hands on my shoulder, and I felt my throat close up.

"It's not goodbye, Percy. I will see you again, in some way. They need you now. You are one of the leaders. Beat Gaia, save the world," she groaned. She was doing a spell, and I could see the toll it was taking on her.

"We need you," I argued with her.

"If it's meant to be it will, Percy. The Fates will get what is planned. I will shut the door and make sure no one can open it again."

She pushed the door closed further, and I helped her pull it. Only our faces showed now.

"Promise me you will fight," I begged her. "Fight until your last breath, Addie. We'll get help-"

"Percy, I promise, until I meet Charon at the gates. I will keep fighting. Tell Athena that I want to come back if I am still alive," I heard her say strongly. "If I die, I'll die happy knowing I helped my brother. Now, GO!"

As she shut the door, I saw the determination on her face. I pulled with all my might, and as soon as the doors shut, a ripple of force knocked me back. Rocks started falling down everywhere.

All the demigods were fighting hard. Most of the army was now gone. Frank was commanding some ghosts to kill the last of them. I do not really remember what happened. I only remember flashes of what was going on around me. I remember slashing and stabbing my way through some monsters. I remember Annabeth grabbing my arm and yanking me forward after she killed an earthborn who was about to clobber me. Frank (as a lion) and Leo were both spreading chaos and fire among our enemies, turning them to ash.

Suddenly it was quiet. The others ran up to Annabeth and me, hugging us and welcoming us back. My eyes did not leave Annabeth's, because the same look that was in her eyes was in my own. Rage, anger, loss...all of them tore through me. Annabeth walked up to me, concern on her face. Every breath I took felt like it was dragging.

"Percy?" Hazel asked uncertainly. She reached out a hand, but Annabeth stopped her. I finally felt my energy leave me, and I fell to my knees.

I could not understand why a single tear was running down my cheek. Maybe it was shock. I knew they all were standing around me, and Annabeth was kneeling next to me. I looked up at her, and the words in my head, the thought I couldn't process, came out. It was just a whisper, just loud enough for Annabeth to hear.

"It's not fair."

She wrapped her arms around me, tears glistening in her own eyes.

I had just left my sister in Tartarus.