Players who create a new 23rd century captain will be eligible to receive specialized traits and bundles of faction-appropriate marks; progressing far enough through the game’s story arcs with your time-lost captain will even enable you to spread those traits to every character on your account. You’ll also be able to advance through all of the same content that’s existed in Star Trek Online for some time, combining the best of all possible worlds. So get ready to make yourself a temporal agent when the expansion launches, and try not to think too hard about the chronological implications. Down that road lies madness.
Source: Official Site