Author's note: Thank you for reading! This is the final chapter. I know it doesn't answer everything, but... You didn't expect to get all the answers, did you?

Chapter 20: Home

Rumi, trans. Coleman Barks

You're from a country beyond this universe,
yet your best guess is
you're made of earth and ashes!

You engrave this physical image everywhere
as a sign that you've forgotten
where you're from!

The machine wasn't much to look at; a bit like an oversized telephone booth with extraneous wires, a large computer extending from the top at an odd angle, and a heavy battery at the base. It was marked off with precise measurements on the floor; in that exact spot in the same lab in another dimension, there was a structure of similar dimensions made of steel and filled with water to the exact weight of this machine plus Peter and Olivia. The way the machine was designed, it would lock on to the mass of the object on the other side and transport it back to this universe as they left it. The exchange of mass, if it worked correctly, would prevent the machine and its occupants from being pulled back to fill the vacuum they left.

"Are you sure that thing will move?" Olivia asked.

"Well, it doesn't have to move very far," Peter explained. "In fact just about a micron. It's just in a direction that we don't have a word for yet."

"I've calibrated the machine to home in on the signal matching the specific vibration emanating from Miss Olivia," Walter said proudly as he removed the electrodes from Olivia's skin. "That should take you back to your universe. And I've sent a message to Walter Prime to let him know you're coming."

Olivia's eyebrows rose. "'Walter Prime'?"

"It's what we're calling the version of myself from your universe. We argued for quite some time over which of us would be Prime. He compromised by suggesting he could be Walter Prime and I could be," he interrupted himself with a chuckle, "Walter Ace."

Olivia smiled.

"And he will of course contact me to let me know you have arrived safely."

Peter looked over the contraption and frowned slightly. "Olivia, maybe I should go over first to test it, make sure it's safe."

"I'm sure it's fine. You built it, and I trust you."

"But still..."

"Besides, if something does happen to you, and we get separated again..." She took his hand. "What would I do then? We're going together. We'll take this risk together."

Agents Dunham, Lee, and Farnsworth were all there to see them off.

"Well," Peter said, "we might as well get this over with." He turned around and addressed Walter. "Thank you for your help. Thank you so much."

The man smiled and shook his hand. "Tell my counterpart that he is a very lucky man to have someone like you as a son."

Peter nodded. He shook hands with the three F.B.I. agents. "Thank you."

"And you," Agent Dunham said. "Your help with our cases has been invaluable."

"It was nice knowing you. Maybe we'll see you again someday," Lincoln said.

Astrid was near tears when she shook his hand, then gave him a hug. "I'll miss you, Peter. Take care of yourself."

Olivia said her goodbyes, then they both turned toward the machine.

"Well, here goes nothing," Peter said.

They stepped inside. Peter bolted the door behind them, then turned to the computer built into the wall. He ran a quick double-check on his calculations, then took a deep breath. "You ready for this?"

She nodded, then wrapped her arms around him. "I love you, Peter."

"I love you, Olivia."

They held each other for a long moment, and then he pressed the enter key.

The machine began to hum, low and slow at first but then louder and faster. Olivia saw a glimmer spread through the metal walls. She heard a clank. And then the glimmer died, as did the humming sound.

"Did it work?" Olivia asked.

"One way to find out." Peter opened the door.

They stepped into a lab identical to the one they just left.

Walter was standing in front of a table, Astrid at a computer console nearby. They were both staring at them.

Astrid's face broke into a smile. "It worked!" she laughed in delight. "Walter, it worked!"

Walter took a couple of slow steps to Peter. "Son?"

Peter breathed. "Dad."

A second later, Walter embraced Peter so tightly he gasped.

Astrid went first to Olivia. "I'm so glad you're back."

"I'm sorry. I'm sorry I didn't tell you what I was planning."

She glanced at Peter. "I'm just glad it worked."

Olivia looked back at the machine that had brought them both back, and compared it to the machine that had taken him away. This one was smaller and far less sophisticated, but still...

This one was a prototype. The machines had the same designer. It didn't make sense, but she was sure of it. She hadn't told Peter what Alia had told her, or even that she'd seen her. Not yet. Not until she was sure she understood what it all meant.

Peter put his arm around her. "What's wrong?"

"Nothing," she answered, and smiled so brightly he almost believed it. "It's just good to be home."