Freddi is a member of the World Aquanaut Security Patrol. She had been Gordon Tracy's partner during his time at the organisation.
In Crab Grab!, Freddi captains a deep-sea craft, and along with Wing and Dave they are sent to investigate mysterious sonar readings originating in the Pacific Ocean. To their shock they trace the readings to what appears to be a giant crab roaming the seabed, which begins to chase, attack and eventually disable their craft. With the power gone, and their oxygen supply quickly dwindling, Freddi puts out an emergency call into International Rescue. It is not long until Gordon in Thunderbird 4 arrives, who also comes under attack from the giant crab and discovers it is actually a robotic craft, before disarming the 'crab' by cutting off its pincers. Freddi watches on, impressed at the aquanaut's skills, and begins to suspect she recognises him. However, Freddi and her team are still not out of danger yet - the skirmish has dislodged some boulders from a nearby rock feature, which threaten to crush their vessel. Thinking quickly, Gordon fires a missile at the largest boulder, which breaks it up before it can bring the craft any harm. Finally free to attach a tow rope, Thunderbird 4 hauls the craft back up to the surface, without its occupants ever realising who was controlling the sub.