Dr Sakho Cato was a 39th century scientist who worked as Professor Charles Feige's chief assistant on Zoda-Kappa.
Cato met Hebe Harrison and went into the forest with her where Lydia Betancourt cut Hebe off from the Holomorph using a psionic inhibitor. Returning to the facility, the three of them stopped the Sixth Doctor's execution and worked to defeat the Holomorph, completing a transmitter to do so. (AUDIO: The Dream Nexus)