On my seventh trek through Middle-earth, this is what I saw:
Seven rings for the dwarf lords
Six Uruk-Hai
Five Narsil shards
Four traveling hobbits
Three rings for the elf kings
Two shades of Gandalf
"So… what's different?" Gandalf the White asked after a moment.
"Nothing, as far as I can tell," Frodo answered. He turned around, scanning the room. "Nothing, same old-"
"Oof! Get off me!"
"Oops!" Frodo had stepped on a grumpy ring. He took a step back.
"Oi, now you're on me!"
"Sorry, sorry."
"Hey! Gerroff!"
"Sorry!"
"Watch it, you big oaf!"
Gandalf rescued Frodo by picking him up and setting him on a chair. From up there, Frodo could see why he had had so much trouble finding a place to stand- the floor was seemingly covered in busy rings, rolling in every direction.
"They're the seven dwarven rings," Gandalf told him.
"How do you know that?" Merry asked. "They won't hold still long enough to count…"
"Exactly," said Gandalf. "They act busy even if there's nothing to do. Very like a dwarf, if you ask me."
"Busy?" Sam said. "Busy with what? What can rings do?"
The seven rings froze in their tracks. "We can dig!" they all shouted, and proceeded to demonstrate. In moments all seven had disappeared into an increasingly deep hole in the floor. Gandalf and the hobbits peered down, but soon the rings were lost in the dark.
"This is boring," Sam muttered, and wandered away, followed by the other hobbits.
"Hello there! How are you today?" Narsil called.
"Who is it talking to?" Sam wondered.
"Who cares, as long as it's not us," said Merry.
"No, really," Sam looked around the room, "there's nobody there."
"Of course there is," Narsil said. "The man with the long beard. Who looks remarkably like that other man with a long beard."
The hobbits glanced over their shoulders. Gandalf the White was still crouching by the hole listening to the dwarven rings work. They looked back out at the room. There was still nobody there.
"You don't suppose it can see Gandalf the Grey, do you?" Frodo asked quietly.
"Well, we can find out," Merry said. He turned to the sword and asked, "Hey, Narsil, can you describe this man you see? Like, what color is he wearing?"
"Oh, sure! Hmm, that's a good question. Might be… purple?"
"Purple?!"
"I didn't know anyone wore purple," Pippin panicked, "I mean, white and grey I've seen, brown and blue I've heard of, but purple? He must be so powerful that he can wear strange colors without being seen!"
Frodo thought hard. "Wait a minute. How likely is it that there are two invisible people wandering around in here?"
"Not very," the other hobbits decided.
"And have we heard any verses about purple wizards?"
"No."
"So the most likely explanation is…"
"That he got in here by being more powerful than the all-powerful song, isn't bumping into Gandalf the Grey because he already got rid of him, and he's here to kill us all!"
"No, Pippin! The sword is colorblind!"
"Oh. What a relief."
"Narsil, can you see if the man is wearing any jewelry?" Merry asked.
"Sure can, he's got a rather gaudy green ring on."
"I'm betting it's gold, and that really is Gandalf the Grey he's seeing, wearing the one ring," Frodo declared.
Merry said, "But Gandalf the Grey is invisible. How can Narsil see him?"
Frodo shrugged. "How can it see anything? Narsil doesn't have eyes."
"That really didn't answer my question, you know."
Sam was thinking hard. "Narsil? Can you remember the whole time you were broken?"
"Well, sure, and let me tell you, it was-"
"Then you must have been able to think even in fragments," Sam interrupted. "Which means…"
"If Narsil can see invisible people…" Frodo mused.
"And if Narsil was in pieces…" Pippin added.
"Then we could all carry a piece of Narsil, and let it guide us as to where Gandalf is!" Sam finished.
"Brilliant, Sam!" Merry said. "That's the only possible way to fight someone you can't see!"
"Well," said Narsil, "that certainly sounds like it would work… wait, did you say- pieces? You're going to break me again? No!"
"Grab it!" Frodo shouted. The hobbits leapt on the sword as it tried to roll away. "Jam it under something!" Sam called. Merry stuck the point under one of the sofas and began leaning on the other end. Pippin pushed a footrest under the sword to act as the fulcrum and sat on it.
"It's not working," Merry gasped. "Frodo, help me!" Frodo reached up and started tugging on the hilt with Merry, but it still wouldn't move. "Sam!" Sam scrambled over and, grabbing the end, swung himself up so that he was hanging from the sword.
Narsil was bending and grumbling about it, but not breaking.
"It won't budge! We need more people!" Frodo called.
"But there is no one else!" Sam said.