Todd and the other members of the expedition were based in a dome on the planet's surface, having been sent to check its suitability for colonisation as their unnamed mother world (presumably Earth) was vastly overpopulated. There were originally six in the expedition, but three — one of whom was named Roberts — left to explore the surface in the TSS machine and for unexplained reasons never returned. Todd experimented upon the native Kinda and surmised that they communicated telepathically.
When Sanders also left to explore, the mentally unstable Hindle took charge. Hindle had Todd, the Fifth Doctor and Adric imprisoned. Sanders returned with the box of Jhana and Hindle had the Doctor open it with Todd present. Despite her fears, the box had no ill effects upon her.
A power cut allowed the Doctor and Todd to escape imprisonment and leave the dome. They met with Panna, the blind wise woman of the Kinda. Both the Doctor and Todd bore witness to a shared vision of the Kinda. They returned to the dome and confronted Hindle. After the Mara's defeat and the restoration of Hindle's sanity, Todd told the Doctor that she would declare the planet "uninhabitable." (TV: Kinda)