A black sphere appeared in the Trappist-1 star system, growing from a few centimeters to ten kilometers in width in a matter of seconds.  Out this sphere ships began to emerge, mostly civilian ships, but with a few military frigates mixed in should they encounter hostiles in this system.

On the six inhabited worlds, not including the penal colony and Kuiper belt which had only basic security ships, local vessels scrambled to launch.  By the time they lifted off, though, the massive hulk of the dreadnought Nero, over six kilometers in width came trough, the void sphere shrinking behind it as it exited.

"Wormhole collapsed" said man on Nero's bridges, reading a screen before him.

"Very well, Sergent." a man in a high General's uniform said, standing at ease in the center of the room, surrounded by a vast holographic display.  Though as the last high general alive he automatically inherited the title of Emperor, he didn't feel comfortably using it so soon after the devastation of Earth by Nebula.  "Status of the hyperdrive?"

"Online and fully operational," replied the Sergent, "though exotic matter reserves are at 7%.  It will take about 23 hours to fully regenerate our reserves so that we can open another wormhole large enough to move the fleet."

"Very well, then.  Hail the nearest planetary authority and inform them of our refugee status."

A console beeped and the airman on duty on communications spoke up.  "They've already sent us a message, sir.  Direct Tachyon Beam transmission."  The airman pushed a few buttons and a male voice came over the bridge's speakers.

"Unknown flagship vessel, this is Odin Space Command.  The Empire is not welcome here.  We warned you never to send another military vessel into this system when we won our independence.  Leave immediately or we will be forced to defend ourselves against your invasion."

Multiple blips appeared on the bridge's tactical displays as ships used their tachyon drives to travel at several C to rendezvous near Odin, the fourth planet in system and the nearest one to the Imperial fleet.

"Mostly frigates, sir." a different Sergent said.  "A few capital ships.  Most of the transponder codes are in our database as old independence fleet vessels, though they've been refitted, some with singularity torpedoes."  Singularity torpedoes were knew technology 170 years ago when this system had succeeded.  Apparently they'd continued the research.  "No match for the military fleet, but if they decide to attack civilians, they could kill a lot of people before we stopped them."

"Understood, now, please follow my order.  Inform Odin Space Command that we are just refugees looking for a place to resupply and rest."