In 2409, Starfleet detects an anomaly in the Azure Nebula and sends the Character (in my case, that was Cpt. Okram bim Terev of the USS Temeraire) to investigte. Upon scanning the anomaly, the timeline changes!
Terev is now a freigther captain running for the Tholians. We are now in the War Timeline of TNG Yesterday's Enterprise.
Here, history took the following course:
The Klingons defeated the Federation and resistance was mounted. The Bajorans discovered the wormhole. The Breen and Cardassians joined forces with the Dominion, which conquered the Alpha Quadrant (Earth and Qo'noS are destroyed). The Tholians remained free thanks to a non-aggression pact with the Dominion. Section 31 is either non-existent or powerless.
On a Tholian base in the Azure Nebula, Captain Terev is approached by Lt. Richard Castillo, who begs for help to restore the timeline. Apparently, the Klingon weapon fire changed the direction of the temporal anomaly. Instead of going back to Narendra, the Enterprise-C travelled further into the future, the year 2409. Now the ship is in Tholian hands and the crew serves as workers.
Terev supports their effort. Not interesting for TrekLit, but nice continuity porn for STO players: Terev encounters numerous familiar faces on the station (including Va'Kel Shon, really captain of the Enterprise-F). Some of them are only alive in this alternate timeline (e.g. Klingon war criminal B'vat).
Skipping the escape plot action; Terev, Tasha, Castillo and T'nae (originally Vulcan Starfleet admiral) free and board the C, beaming the about 100 C survivors back on board. A Tholian flottilla attempts to prevent the escape and is likely to succeed with ther Tarantula-class dreadnought. Then, however, the Wells-class timeship Pastak appears, destroyes the dreadnought. The Pastak and C fight together and defeat the Tholians.
Before the Enterprise enters the properly calibrated anomaly to finish the Battle of Narendra, Terev is beamed aboard the Pastak. Captain Walkers intents to restore the timeline and does not want Terev to go back in to the past, spoiling it further. Moreover, her participation in important events of the 25th century is vital.
The timeline is restored. The Temeraire scans for the anomlay, but it is goen. Nobody knows about the events.
Reward: playable Ambassador-class support cruiser, Yesterday's Enterprise uniform.