“… requesting assistance. We have sustained significant internal damage and multiple injuries. But keep clear of the flare at all costs! Shields had no effect. Repeat, deflector shields had zero effect on the phenomenon. The bursts formed directly inside the ship.”

“T’Viri is closing on them,” Chung said. “They’re nearer than we are—and that thing is between us and them.”

Blake grimaced. “Then we’ll trust them to do their part and we’ll do ours. Keep studying the vacuum flare. Learn everything you can.”

“It’s finally starting to subside, Captain,” Uhura reported.

“That’s good. But if this one got so much bigger and more dangerous than expected,” Blake wondered, “then what about the next one?”

U.S.S. Reliant

By the time Reliant made it back to the Federation’s core sectors nearly three weeks after the Deneva incident, two more vacuum flares had occurred, in the Cygnet and Makus star systems. Both had been in empty parts of the respective systems, doing no damage except to a passing comet in the latter, but both continued the pattern of growing larger and lasting longer than the previous ones.

“Starfleet is taking this as a serious threat,” Captain Terrell told the assembled command crew in the main briefing room. “Every one of these vacuum flares has occurred in a major Federation or allied system. At this point, it’s unlikely that it’s random.”

Terrell’s first officer, Rem Azem-Os, flexed her green-and-gold wings thoughtfully. “Every one we know of,” the venerable Aurelian replied in her fluting voice. “If it’s happening in uninhabited or precontact systems, we might simply be unaware of it.”

Chekov shook his head. “The major Federation observatories have been scanning for similar bursts. The gravimetric surges would be detectable on subspace bands, but there’s been nothing, except from these five systems.”

“So is it some kind of attack after all?” asked Lieutenant Mosi Nizhoni, the chief of security.

Commander Beach spread his hands. “Not necessarily,” the helmsman told the younger Navajo woman. “For all we know, this could be some kind of natural phenomenon resulting from repeated warp travel in those regions. Maybe we’ve worn potholes in subspace.”

“There’s been far more warp travel around Earth, or Vulcan or Andoria,” Chekov countered.

“What is it that these five systems do have in common that others don’t?” Terrell asked, impatience tingeing his voice. “Argelius, Altair, Deneva, Cygnet, Makus. What’s the common denominator? How can we predict the next system to get hit?”

Chekov opened his mouth, but hesitated. Azem-Os caught it. “You have a thought, Commander?”

“It’s… tenuous.”

“That makes it no different from anything else about this situation, Pavel. Tell us.”

“Well… I couldn’t help but notice that all five of these systems have been visited by the Enterprise.”

Beach shrugged. “They’re major ports. Hundreds of Federation vessels have visited them.”

“In reverse order?”