On the thirty-fifth day, the global fusion process entered a stable phase.
The overlapping zone in Berlin stopped expanding, evolving into a permanent "superposition area". There, people could choose to enter the Berlin of 1945 or the Berlin of 2025—or even a hybrid of both. Residents could choose which era they belonged to, switching between them as often as every day if they wished.
Similar phenomena began to emerge in other cities around the world. New York developed an overlapping zone between 1929 and 2025, Tokyo between 1945 and 2025, Shanghai between 1937 and 2025.
Mirror humans began to adapt to this new reality. Some chose to live alongside their "other selves", sharing two sets of memories and becoming more complete individuals. Others chose to keep their distance, insisting that their own version of events was the only "real" one.
Ethan and Mason chose a third path: They moved into a newly built "Timeline Fusion Experimental Community" in Harborview. The community was specifically designed to accommodate mirror humans who had undergone deep fusion, helping them manage their multiple sets of memories.
Within the community, everyone was "plural". Some had two versions of themselves, others three, and the most extreme case had seven—corresponding to the seven major divergences that had occurred since 1945. They lived together like siblings, sharing the same past up until their divergence point.
"How are you feeling?" Dr. Zhou asked during a visit to the community.
Ethan—or was it Mason? They no longer made a distinction between themselves—thought for a moment before answering. "It's like having multiple lives. I'm both a programmer and a photographer. I've lived both in Harborview and in New York. I've experienced both my father's illness and his success."
"Isn't it confusing?"
"It was at first. But now... it's like reading a very thick novel, where the protagonist made different choices and followed different paths to different endings. And I am the sum of all those endings."
Dr. Zhou looked out the window. Inside the community, people were going about their daily activities—some playing chess, some painting, others discussing physics. They looked just like ordinary people, except for the occasional moments when they would make the same movements or say the same words simultaneously—a residual effect of the fusion, where mirror humans would unconsciously sync up with each other.
"What will become of the world?" Ethan asked.
Dr. Zhou fell silent for a moment. "Dr. Owen's team predicts that eventually, the entire globe will evolve into a state of 'multiverse reality'—different regions will be dominated by different timelines, and people will be able to travel between different versions of the world. History will no longer be linear—it will be a web of possibilities. You could live in 1999 on Monday and 2025 on Tuesday if you wanted to."
"How will history be written then?"
"History will become... a choice. You can experience whichever version of history you prefer by visiting the corresponding region. You can believe whichever version of reality you choose to accept."
"That sounds beautiful."
"It can also be terrifying," Dr. Zhou said. "Because it means that reality itself has become subjective. There is no objective truth—only consensus reality. And consensus can be manipulated."
Before leaving, Dr. Zhou handed Ethan an encrypted USB drive. "This contains the complete archives of the Time Observers. It includes records of every fusion event in history, and... predictions for the next one."
"When will the next fusion occur?"
Dr. Zhou didn't answer, instead giving him a meaningful look.
Ethan returned to his room, plugged the USB drive into his computer, and tried to access the files. The archives were protected by multiple layers of encryption. He tried combining his own birthday with Mason's—it didn't work. He tried June 28, 1999—the day their SAT scores were released. It worked.
The first page of the archive read:
"Timeline fusion is a cyclical phenomenon. Current cycle: The Seventh Great Fusion.
Predicted window for the next Great Fusion: 2045–2050.
Trigger event: Unknown.
But all signs point to one possibility—the artificial intelligence singularity."
Ethan kept scrolling, coming across a graph showing that the frequency of timeline fusion events was increasing exponentially. The first large-scale fusion occurred in 1945, the second between 1999 and 2025, the third predicted for 2045–2050, followed by another in 2080, then 2100... The intervals between them growing shorter and shorter with each cycle.
Eventually, around the year 2150, the curve shot upward toward infinity—indicating that fusion would become a continuous state, time would lose all linearity completely, and all possibilities would exist simultaneously.
At that point, humanity would no longer be "beings existing within time"—they would become "beings existing within possibilities".
Outside the window, a strange glow had appeared in the sky over Harborview. It was the result of two versions of the sky overlapping—one a slightly polluted gray-blue from 2025, the other a clearer azure blue from 1999.
Two worlds, breathing together under the same sky.
Ethan closed the archive, walking over to the window. The lights on the opposite shore of the Harbor River still flickered, alternating between bright and dim. The sound of the river's current drifted up to him—the same sound that had echoed through the centuries, bearing witness to countless versions of Harborview on both banks, countless versions of human lives.
His phone buzzed with a text message from Mason:
"Do you remember that spring during our junior year of high school? We were studying by the river, and you said you wanted to build a time machine."
Ethan replied:
"You said you wanted to capture every fleeting moment with your camera."
"Now we have our time machine," Mason wrote back. "The entire world is one giant time machine."
"And we are its first passengers."
Ethan set his phone down, gazing out at the dual sky above him. He didn't know what the future held—whether it would be a utopia of multiverse reality or a chaotic end to everything. All he knew was that the world had changed, and once change had begun, it could never be stopped.
Just like the waters of the Harbor River, flowing from the hills, branching off into countless tributaries, yet ultimately merging into the same vast ocean. Every drop of water chooses a different path, but all paths lead to the same destination.
Perhaps time is the same way. All divergences, all possibilities, will eventually converge somewhere.
And what will that convergence look like?
He didn't know.
But he knew he would live to see it.
Because now, he had all the time in the world—or rather, all the possible times in the world.