Blackstar’s opening theme ~slightly paraphrased~ does a good job of summarizing the show:
“Astronaut John Blackstar was swept through a black hole, into an ancient alien universe. Trapped on the planet Sagar, Blackstar was rescued by the tiny Trobbit people. In turn, he joined their fight for freedom against the cruel Overlord, who ruled by the might of the Powerstar. The Powerstar was split into the Powersword and the Starsword. And so, with Starsword in hand, Blackstar, together with his allies, set out to save the planet Sagar.”
Blackstar allied himself with the sorceress Mara, a shape-shifter named Klone, and a fire-breathing dragon steed, called Warlock. When not thwarting the evil schemes of Overlord and his mob of minions, the companions hung out with their tree-dwelling friends, the Trobbits. The Trobbits, who had an assortment of unique but minor abilities of their own, oftentimes found themselves embroiled in the action.
The show lasted for a single, thirteen episode season. Stylistically, it was a revealing precursor to Filmation’s later but better known fantasy epic, He-Man and the Masters of the Universe.