(Recap: Artemis could here the voice of Percy mentally smirking. She wasn't proud of it, but she had stopped Percy just as he was retreating in anger, despising the idea of being a spy less than the idea of Thalia being tortured in Tartarus. So she'd agreed to become his spy.
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"Okay, you do it in your own time. Meanwhile, what's next? Our plan working out fine?"

"Excellent. Tartarus isn't gonna know what hit him." Percy smirked at the big three.)

The big three had known for a while about a possible attack from Tartarus. All the murder accusations on Percy were untrue. The entire execution was faked, a plan laid down so that a stage could be set up where Percy would lose his memories and systematically enter the ranks of Tartarus and his army. That wasn't all of the surprises though. The person taking care of Thalia in Tartarus right now was none other than Iapetus, the Titan that was pushed in the lethe by Nico, Thalia and Percy. Iapetus had come a long way since losing his memory. He'd befriended Nico, Percy and Annabeth. He'd helped Percy and Annabeth wade through Tartarus safely while sacrificing himself to Tartarus. However, with the entry of Percy in Tartarus' numbers, Tartarus thought it best to give Iapetus another chance. He needed generals, and since the other Titans weren't destroyed by him but by the demigods, they'd never be reborn before centuries passed. Lucky for Kronos if he managed the feat even in a millennium. Thus the titan was born again, and unbeknownst to Tartarus, he had chosen to remain Bob. Iapetus was the same Titan Percy was referring to earlier when he'd threatened Thalia speaking that this was a year of lost memories being regained. Bob had convinced Percy that he was with the Gods. That was one of the major reasons he could sneak out safely without worrying about Thalia. Once the meeting with the big three was over and he'd gotten the nod for phase two, he began thinking of ways to get Thalia out of hell. She was in a pitiful condition, but the place was literal hell. Just being in there and being against the pit was torture. No one needed to make you bleed or expose you to pain. He feared that if the release took more time, Thalia might suffer a mental trauma she could never come out of. Sure, he was trying to keep her safe and so was Bob, but they were running out of tiny unhurtful tortures that would look bad but not pain that much to execute on Thalia. And obviously, she wasn't even close to breaking. So if Tartarus decided to take matters into his own hands, they'd be in a load of trouble.

Phase two included infiltrating the secret places within Tartarus and finding out ways to destroy the pit. Percy sure wasn't going to host Tartarus, but there was gonna come one time when Tartarus would ask. He didn't wanna be there at that time. That was supposed to be the shock, one that would break his legs. Then the pit would be destroyed so that that would be the end of monsters. Tartarus wouldn't have a conscience then, so he would be destroyed along with the pit. A very far-fetched plan if you thought carefully. Tartarus was basically the pit, and Percy didn't know how he could be inside a primordial without the primordial's knowledge. And he had to search every part of him. Easy peasy, right? Apparently, it's easier said than done, or so they say.
This was only half the story of course. The rest was Tartarus. Even he had ordered the beginning of his phase two. Percy was torn in pieces between the phase twos. However, he was more worried about Tartarus' phase two since it involved him going to one of the camps. With an army, to threaten them and try to steal their numbers. And officially announce that he's a traitor and soon-to-be host of Tartarus.
As soon as he reached an opening in the woods, he sheathed his sword and muttered some words in ancient Greek, creating a small rupture in the mountain that lay ahead of him. Percy entered the opening and immediately went to see how Thalia was doing. It took him a few minutes to walk that distance but turned out it was a great thing. He could already feel an idea shaping itself in his head. One that could begin Tartarus' phase two and help Thalia escape at the same time. He saw thalia's nose bleeding, wrists bleeding and her screaming in anger. Colourful words for Tartarus that was definitely not praise flowed from her mouth. Percy knew that Tartarus was an evil, cunning, egoistic jerk, but unlike the enemies he'd faced, Tartarus was not impulsive. He wouldn't wanna destroy Thalia just because she said some names. But at the same time, he was pretty calculating. He'd have realized by now that Thalia is not at all being tortured as she should be in a place like Tartarus. Otherwise even her, as much great a warrior she is, would've broken by now. Percy and Annabeth sure would've, but they had each other. Thalia was no different from them. Sure, she was strong and brave and rash and fearless, but not enough to sustain Tartarus. And once the pit God realized that he'd come to her, break her himself, then Percy and Iapetus would be answerable. The thing about Tartarus though was, he didn't get pissed off that easily. But if he did, he only had one punishment. Death. So he figured thalia needed to shut up, and he needed to talk to Tartarus about his plan. He beckoned Iapetus from his guard duty. When Thalia saw Percy, she stared at him with hate and disgust, but also a little worry. She still thought Percy had been brainwashed.
"Iapetus. Shut her up before she pisses of the pit. I have a plan and I'm going to discuss it with Tartarus. Come with me. But shut her up first."

Iapetus nodded, gagged Thalia with a piece of cloth which muffled her insults and then they proceeded to meet Tartarus.

Both of them stopped outside of a room which Tartarus called 'the summoning room'. Whenever somebody wanted to discuss something, they were supposed to come here, stand outside and wait for him. He'd feel the presence and his voice would speak from the inside. Nobody was allowed inside, but Percy and Iapetus preferred it that way. Not because they weren't curious, but because the ones that went inside were unheard of since then. Never came out.

"Perseus, Iapetus. Why have I been summoned?"

They bowed down (I know what you're thinking... Percy never liked bowing down to the Olympians but here he is, bowing down to the mastermind evil who wants to destroy his home? Well let me tell you, undercover stuff is difficult. If he can hurt is own sister to maintain secrecy, he can surely bow. And if it saves the camps and the world, he'd bow a million times.)
"Lord Tartarus, I have a plan that can guarantee the success of phase two."

"Why do you need a plan Perseus? Didn't I tell you what to do? Go to one of the camps, threaten them with a huge army, ask them for support against the other camp. They haven't made peace yet."

"Yes my Lord, but that doesn't guarantee a success rate. I have something extra to add."

"And what might that be?"

"Thalia's state is a mess. The campers are all in a state of confusion. If they see her like this, they'll break. Your plan is to ignite camp against camp. Mine is to demolish half-blood."

"You want to show them Thalia Grace? What good will that do? If I've learnt anything observing the past two wars, it's that death makes your kind more nervous. They rally around a hero and double their strength by sheer motivation. I'm not a fool unlike my wife or children, I know the effect and power of love. Your plan might backfire."

"Your logic is correct my Lord, but you misinterpret my plan. They'll have a hero to rally around if I give them one. There's no one in half blood capable of leading. Piper sure is a good charmspeaker, but when they have a war against Rome, she herself will be torn because Jason will be torn. Annabeth will be devastated on seeing me, so shall the hunters on seeing Thalia. And Chiron won't have a thing under control once the leaders are rendered mentally useless."

Percy and Iapetus couldn't see it, but Tartarus was smiling at them, beaming even for coming up with such a wonderful plan.

"I underestimated you, Jackson. You're not underrating love at all, you're using it to exploit their minds. Magnificent. But then you understand that for this to work, you have to go to Rome first, without the daughter of Zeus. Convince them to announce war on the greeks. Then when the Greeks are torn enough, you go there with Thalia and demolish any hope they had. That way more demigods will join us, and it'll be much easier to attack Olympus during the war as they'll be torn between their Greek and Roman forms because of war amongst their children."

"That is precisely what we plan on doing. Under no circumstances should the Roman camp know of the capture of Thalia Grace. She is a good friend of the Praetor's sister - the amazon queen Hylla. So she'll most likely not support us if Thalia's situation were to be compromised. Could you tell all our numbers to keep their mouths shut during the meetings as a direct order from you? I'll have to lie a lot there and if one of them were to rashly speak, the entire plan will not only fail but even backfire in the form of a united front of demigods."

"Consider it done. Good work Percy. You'll soon get your revenge, you're working very hard for it."

"Thank you, my Lord. I owe it all to you. Now, if you'll excuse us, we have to plan a certain downfall." Percy and Iapetus fake smiled.

"Of course. Go Percy and Iapetus. My army shall not speak unless you command them to. You have my word."

"Thank you." Percy and Iapetus bowed and proceeded towards where they'd kept Thalia.

It was a perfect plan for Tartarus, absolutely flawless. Or was it? The biggest flaw was the planners weren't thinking of Tartarus, but the plan sounded pretty full proof, right? So what was in it for Percy? The Roman camp. He would take Thalia with him and keep her locked a little far away in the hands of a few monsters. Then he would speak in a way that only his friends could understand his plan. If they didn't, he would have no choice but to blow his cover, bust Thalia out himself then wait for doomsday seeing as they didn't know of a way to stop Tartarus once he got powerful enough. So the fate of the world depended on Percy once again. Huh, what's new, eh?

(A/N: PLEASE VOTE AND COMMENT, CONSTRUCTIVE CRITICISM IS APPRECIATED.)