When Starfleet gave a warning surrounding Federation vessels disappearing in the Laurentian System the Starbase was put onto alert -- and when it was discovered that starbases from the Republic and Empire had been destroyed, it became evident that 777 may be the next target. Orders were given to evacuate all civilians and non-essential personnel to the USS Eventide in what would be its first deployment. The ship's progress was swiftly halted by warbirds blocking the way and the station found itself with its power disabled somehow, leaving them defenceless to a mercenary raid.
When the mercenaries fought their way to Starbase Operations it was revealed that they were here in order to obtain equipment, supplies, weaponry, and servants. 777's officers officers successfully managed to ward away a fair number of the mercenaries but it was then found why they had began to retreat: the station had been rigged to explode. It was with the expert work of Engineering and Operations officers that they managed to disable the explosive device and save the station from further harm.
Eventide - despite being under attack - managed to transmit a distress call to Starfleet who reported that their closest vessels were an entire day away. Eventide managed to hold off continued attacks and hold out until the arrival of a rescue fleet which successfully towed them back to Starbase 777. With the ship and starbase both heavily damaged masses of officers beamed aboard to help in the efforts to treat the wounded and repair the damage. With 80% of its crew having perished in the siege, the attack here was noted as a true tragedy for Starfleet.
When it was revealed by the prisoner General Akrij Kuntoj - who had been behind the recent attack - that a large number of 777's deceased crew were not deceased but had instead been taken captive by the mercenaries, investigations were immediately launched. It was discovered that these claims were true and with Starfleet Intelligence having pinpointed the location of the mercenary vessels, the USS Eventide was sent to capture the mercenaries and bring their crew back home.
The Eventide was soon engaged in battle with the mercenary vessels but a number of the mercenary ships opted to flee, only to be caught by awaiting backup. With two away teams boarding the U'Chos Sowrick and Vak'ok Guz respectively, the crewmembers fought their way through the ships to uncover where the crew were being held. After their valiant fighting (and numerous close calls) the crew ended up with multiple mercenary crews being arrested and their ships captured... Alongside the retrieval of 5300 Starfleet officers, 1211 Klingon Defence Force officers, 300 Romulan Star Empire soldiers, and 2000 civilians.