Nico di Angelo's moments

What if...

What if- at the end of The Mark of Athena- this happened instead...
We're to the point where Percy just let's go of the ledge and him and Annabeth are falling into Tartarus while Nico still has his hand out, while Hazel tries to pull him away from the ledge.
*
Nico blinked again, so many emotions were thrown at him all in that split second.
Before he knew what he was doing, he stood up, and peered over the edge.
"Nico, no!" Hazel tried to stop him but by then- it was too late.
Nico dived into the darkness, shouting, "Percy! Annabeth! Where are you?!"
A few second later, a few feet below, Perct responded, "Nico, are you insane?! Why would you jump in?!"
A few seconds later, Nico was a yard above Percy and Annabeth.
Annabeth was half sobbing when she looked up at Nico, and with one arm wrapped around Percy's neck, she extended her free hand. Percy did the same, with one arm tightly wrapped around Annabeth.
Nico reached his arms out and took ahold of the couple's hands, then pulled them to him, wrapping his arms around them.
"Ready?!" Nico shouted through the whipping air.
Annabeth yelled a Yeah while tightening her grip on the boys, while Percy furiously nodded.
Nico knew what would happen if he did this, but too much was on the line, he had to.
Slowly, Nico dissolved into the heavy darkness around them, pulling Percy and Annabeth with him.
Suddenly on the deck of the Argo II, Hazel had arrived from climbing up the ladder, tears streaming down her face. The ship flew out of the cave, floating into the air, high above the clouds.
"Where's the others?" Leo asked, then noticed Hazel's tears.
Everyone on deck stopped, and realized what was happening. So much for a rescue plan...
All of a sudden, the shadows that led down to below deck darkened and grew bigger.
With a thud, Percy flew out of the vortex like shadow, an slid across deck. Next Annabeth emerged through the shadow, landing on top of Percy.
There was only one explanation, and that was shadow travel, but the only person missing and was actually capable of shadow travel was nowhere to be seen.
Hazel looked at the still glittering shadow, hoping- just hoping...
The Argo II was quiet for too long, the shadow started to die down to a simple shade.
Hazel burst into sobs just as a figure was shot of the shadow, moments away from closing, crashing into Leo.
"Agh!" Leo groaned, then looked who was on top of him- nothing but thin air.
Hazel whipped away her tears, dazed at what she had witnessed.
As if he was taking off a invisibility cloak, Nico shimmered into sight- then instantly disappeared again.
Hazel felt more confused than heartbroken now.
Nico came back into sight again, but his skin seemed smokey as if he was an Iris Message that Leo set on fire (A/N I'm almost positive that that's impossible, but hey- this is fan-fiction, anything can happen).
Nico seemed uninjured, just exhausted and ashamed; with his skin still smoking- kind of sizzling- he faced the group and said, "I can explain..."