Filmation's experiment with live-action was nearing its end in 1978. The Secrets of Isis, originally part of the Shazam!-Isis Hour, was cancelled after 3 seasons, but Isis would stick around, transitioning into animated form, and form a super-team of her own: The Freedom Force.
There were only 5 episodes of Freedom Force produced as part of the Tarzan & the Super 7 anthology package Filmation put together for CBS. Relative newcomer Diane Pershing was the voice of Isis. Most of today's toon fans might know the actress' name more for her work as Poison Ivy on Batman: The Animated Series several years later.
Here's the intro, uploaded by Hewey1972:
Super 7 would continue for another year on CBS before being shuffled off, without Tarzan, to NBC for its final season, and hasn't seen the light of day since. Later on, we'll review the three remaining segments: Web Woman, Manta & Moray, & Superstretch & Microwoman. Tarzan, Jason of Star Command, & The New Adventures of Batman have all previously been reviewed.