An attractive human woman apparently in her 30s, Karla Five was an explorer and scientist from an antimatter universe parallel to our own. When the crew of the U.S.S. Enterprise observed her small scout ship traveling at the unheard-of speed of warp 36 straight toward the dangerous Beta Niobe stellar remnant on stardate 6770.3 (2270), Captain James Kirk tried to stop Karla Five's vessel by snaring it in a tractor beam. Unfortunately, Kirk succeeded only in getting his own ship dragged through an interdimensional portal into Karla Five's home universe. With the assistance of her son Karl Four, Karla Five found a way to get the Enterprise and her crew back to their home universe, sacrificing her ultrafast scout ship in the process.