There it was. Right in front of him. The black pit, swallowing him up in nightmares, Now for real.
"There's no one else." He told himself. "I have to do this." He glanced back. He saw them all – his friends, the only people alive who he loved. He'd known them all in different ways, and he cared for them all. He'd thought he would never have been able to care for anyone ever again, but he did.
Hazel looked devastated. Frank was patting her shoulder, though his eyes stayed on the dark figure by the door. He gave a single nod, followed by a salute – the Roman way of appreciation. It was the closest his honor-bound culture allowed him to saying 'Thank you'. Jason did likewise, and Piper looked at him with fear, respect and admiration.
The figure by the pit turned his eyes last on Percy and Annabeth, knowing what he would see. Percy was on his knees, and looked as though someone was physically torturing him. Annabeth was beside him, sobbing for once, and they were looking right at him. They both stood up shakily when their eyes met. Percy extended his hand and looked as if he was going to run to him, but stopped dead at the hand which was raised to stop him. A skeletal one. An army of the same skeletons surrounded the six people, the six demigods of the prophecy of seven. Leo had been badly wounded and and had been sent to the ship to get healed and then bring supplies.
The lone dark-haired boy turned his back on the army and his friends. He knew that no matter how hard he fought, the monsters would only resurrect themselves. His only useful act would be to do what he was going to.
Taking a deep breath, he stepped forward and took hold of the doors. His heart was hammering against his ribs and his brain was threatening to shut down. Nico ignored it and closed the Doors of Death behind him, shutting himself in the abyss that was Tartarus.