This trophy is called "Spectres" and it requires you to complete the now unlisted episode (story arc) titled Spectres.
As was kindly noted by KTKarona in the comments, during season 15, Age of Discovery, a lot of the game got revamped. Several missions were removed and others shuffled around to help make a more cohesive story with later released content. One of the moved items was the Spectres episode. It used to occur during the initial Klingon War story arc for Federation players, and later for Klingon & Romulan players, but is now pushed all the way back to the Klingon Civil War episode which is essentially end game story content after reaching Level 65.
Please note that I've read there is a bug where it may only unlock for Klingon players. I unlocked this as a Federation player a few years ago and am unable to personally confirm this.
- "Spectres" - Non-replayable mission.
- "Skirmish"
- "Spin the Wheel"
- "What Lies Beneath"
- "Everything Old is New"
- "Night of the Comet"
Original Solution Information:
- Federation players will begin to earn these missions at Level 11 and it should conclude at Level 15.
- Klingon and Romulan players, this will come later into your stories sometime around Level 30.