Disclaimer: Characters and situations currently owned by CBS.

Thanks to: Likeadeuce, for the valiant beta-reading.

Timeline: during City at the Edge of Forever for the TOS characters, just after the s2 of Star Trek: Discovery finale for Michael Burnham.

Spoilers: until the episodes indicated above.

I. Prologue

Since joining Starfleet, Uhura had experienced her share of hair-raising situations. Her life had been threatened more than once, both on a general level, due to the ship she was serving on being under threat, and on a personal one. More than once, she'd faced a lethal weapon aimed at her. She liked to think she handled herself well under pressure.

She had never been as deeply, existentially frightened as now, doomed to watch images of Earth's history flitting by after her Captain and Mr. Spock had disappeared into the strange portal in pursuit of Dr. McCoy. Dr. McCoy, who'd somehow managed to alter history to an unfathomable degree. There was no more Enterprise in orbit above them. As far as Uhura could ascertain, having tried her best to make contact on any frequency she knew, there was no more Federation , or at least none that had listening posts within range. Uhura was well familiar with the butterfly theorem. For all she knew, every single person she'd ever known and loved might have ceased to exist, at least for now.

"Well, there's nothing to it," Montgomery Scott said. "Nothing but wait." He'd been left behind with her, as well as with security officers Galloway and Lehane; the Captain had told him that if nothing changed and there was no sign history was restored after an appropriate waiting time, each of them was to follow through the portal and try as well, but individually, to heighten their chances.

"Well, at worst, we'll all end up in pre warp drive America," Galloway commented. "There are worse eras, right?"

Uhura knew that he was only trying to keep up morale, but at that moment, she could have slapped him. "For a white man," she said sharply, then caught herself. They could very well be the last survivors of a wiped out timeline. They were in this together.

"Mr. Scott," she said, forcing herself to sound cheerful, retrospectively making her remark into a quip although it hadn't been intended as such, "tell me you're not curious to figure out how exactly this portal works. If nothing else, it must be an unprecedented marvel of engineering, and from a civilization we know nothing about, too. That sounds like your kind of challenge."

Scott gave her a tense smile; she could see he understood what she was doing. "Aye," he said, "and..."

Which was when a sudden, red flare between them and the portal nearly blinded Uhura. Instinctively, she dived behind the next rock. Then she looked again, and blinked. A figure in an armored suit had appeared, two arms, two legs, with the odd mechanical wings unfolded behind it echoing various saurian-based species, at least in looks. For a moment, it hovered about a meter above ground. Then it crashed down on the surface while a voice cried: "No!"

The universal translator was a fantastic invention, but Uhura had trained as a linguist. She prided herself on recognizing a great many accents within the Federation, and back at the Academy, her classmates had challenged each other by playing ever shorter aural clips to identify. One syllable was pushing it. Still, she was reasonably sure it was a human voice she'd just heard.

"Identify yourself," Uhura said, while Scott and Galloway kept their phasers trained at the new arrival.

The figure rose again, opened its helmet, revealing a human-looking female. "Commander Michael Burnham, USS Discovery," the woman said, sounding frustrated, concerned, and not a little angry. "Who are you?"