Well, here's the story.
There was a Kzinti noble who wanted to seize control of the throne, so he started a civil war. This noble, who later came to be known as "the Ususrper", came out on the losing end of the civil war. The ragged remnants of his fleet were being pursued by the kzinti fleet, and preferring suicide to capture, he plunged his ship into a huge nearby radiation field called the WYN cluster. Assuming he was dead, and not wanting to follow him in, the kzinti fleet turned around. But, the Usurper found out that the WYN cluster wasn't a huge cloud, but rather a shell of radiation, which could be survived if traveled through fast enough. And inside that shell, there were many habitable and resource-rich star systems. So the Usurper secretly began rebuilding his power and biding his time. Later, an Orion vessel came through the radiation field, also preferring the apparent suicide of the cluster to capture. They discovered what was inside, and the WYNs and Orions formed a partnership. The Orions also told the outside world, and soon the WYN cluster became a place for all kinds of people who didn't like being among the larger empires. For many years, the WYNs traded with its neighbors(Klingons, Lyrans, Kzintis), and fended off attacks from all of them with a rag-tag fleet of gunned-up freighters and whatever ships they could obtain by various other means. The Orions also operated a shipyard inside the safety of the cluster, in return for a gift of one light raider per year.
The Usurper had been hoarding most of his wealth during his years in the WYN cluster, and had always planned to return to the Kzinti Hegemony to take over and rule. His grandson(who had inherited the title), finally decided that the time to strike was right, and commandeered the Orion shipyard to build a custom-designed fleet that could go toe-to-toe with kzinti warships. These were the "Fish ships", so called because they are named after predatory terran fish by the federation. The Usurper built his new fleet, and launched the WYN War of Return. The War of Return ended with a final battle between the Crown Prince of the Hegemoney and the Usurper. Rather than decimate each other in the face of a growing Andromedan threat however, they had a titanic duel in space control ships. The exact outcome of this duel was never clear to the Federation. It is known that both ships survived and needed extensive rebuilding. It is known(or perhaps is only legend?) that the two badly crippled ships docked and their crews fought it out claw-to-claw. Regardless of who actually sits on the throne now, it seems that life in the Hegemony and the WYN Cluster have returned to normal after this event.
Phew. There you go.