On the twenty-eighth day, Ethan and Mason returned to their high school in Harborview.
This was where their shared journey had begun, and where their paths had diverged. Standing in their old classroom, they saw that the blackboard was the same one they'd stared at during lectures, the desks and chairs had been replaced but the layout remained unchanged.
"If my dad hadn't gotten sick back then," Mason said, "I would have chosen the computer science program just like you did. I would have stayed in Harborview."
"If my dad's company hadn't landed that big contract," Ethan replied, "I might have gone to New York instead. I might have studied photography."
They both realized the same paradox at that moment: These two "what-ifs" couldn't have both been true. Because their father was the same person—in the summer of 1999, Mr. Carter couldn't have been both seriously ill and enjoying a sudden business success at the exact same time.
"But in both of our memories, Mr. Carter existed as a real person," Mason said. "In my world, he got sick, recovered after surgery, and is now retired at home. In yours, his company thrived, and he's now a successful entrepreneur."
"Which one is the real version?"
They decided to find out. First, they went to the address from Mason's memories—an old suburban neighborhood. When they rang the doorbell, an elderly man in his seventies answered. It was Mr. Carter. He looked thin, with the lingering frailty of someone who'd survived a serious illness.
"Mason?" The old man looked at them in confusion, his gaze darting back and forth between the two identical faces. "You two..."
"Hi, Dad," Mason said.
Ethan didn't speak, simply staring at this version of his father. In his own memories, his father was more robust and energetic.
They stayed and talked for twenty minutes. This Mr. Carter remembered every detail of Mason's life from childhood to adulthood, including the serious illness he'd suffered in the summer of 1999. He pulled out a photo album, filled with pictures of Mason from infancy to his college graduation.
Then they went to the address from Ethan's memories—a high-end gated community. The man who answered the door was also Mr. Carter, but this version was much more vigorous, wearing a polo shirt and a luxury watch on his wrist.
"Ethan?" This Mr. Carter also looked stunned. "Why are there two of you..."
"Hi, Dad," Ethan said.
They talked for another twenty minutes. This Mr. Carter also remembered every detail of Ethan's life, including the joy of his company winning that big contract in 1999. He pulled out a different photo album, filled with pictures of Ethan's entirely different life path.
Both versions of Mr. Carter were real.
Or rather, both had been real in their respective parallel universes. And now that the two worlds were overlapping, both versions of Mr. Carter existed simultaneously.
By the time they left the second Mr. Carter's home, night had fallen. The two men who looked exactly like Ethan—they no longer bothered to distinguish between themselves—walked along the old streets of Harborview.
"What are we going to do?" one asked.
"Accept it," the other replied. "The world has changed. There's no longer a single reality—only multiple realities existing side by side."
"But if things keep going like this, it will only lead to chaos."
"Perhaps chaos is just the new order."
They walked down to the banks of the Harbor River, gazing at the lights twinkling on the opposite shore. Those lights flickered too—sometimes bright and modern, sometimes dim and reminiscent of the Harborview of the 1990s.
The world was breathing, oscillating between two different versions of itself.