It is 2376, two years before Voyager got home.
Two years after Voyager's Doctor was able to tell Starfleet that the missing ship was lost in the Delta Quadrant, Starfleet's efforts to make contact with the missing ship bore fruit. Part of the second Data packet sent to Voyager through the MIDAS Array included a message for Captain Janeway from Admiral Hayes - in which the Admiral mentioned two ships had been sent to meet Voyager along the way and help her home.
Those ships are the starships Europa - a Nebula Class Starship outfitted to be a 'floating starbase' - and the Galaxy, a 'Venture type' uprated Galaxy Class ship modified to face any threats the Delta Quadrant might throw at the task force.
Within days of embarking on their historic mission, both ships encountered what appeared to be some kind of Iconian 'super' Gateway floating in space. Closed inspection led to its inadvertent activation - pulling both ships into a completely unrecognisable region of space - theorised to be another Galaxy entirely.
Within moments of arrival both ships were attacked by a powerful alien force - which both ships now seek safety from by staying at warp, refuelling for the short periods of time they can before they are attacked once more.
They are trapped here in this Galaxy. Why will be revealed in time...but for now...RUN!