Yesterday's Excelsior - S2.E2

A glimpse at what could have happened if the original Excelsior, under Captain Hikaru Sulu, had found itself falling through a temporal anomaly on its way to assist Captain Kirk at Camp Khitomer. The Federation has fallen to the Borg, having been punished by the Q Continuum for their massive retaliatory strike against the weakened Klingon Empire after the assassination of the Federation President. What remains is being lead by the Battlestar-class USS Excelsior, as they search for a safe haven, but the arrival of the original Excelsior may provide a way to do more then simply survive.