I'd been looking occasionally for the Sci-Fi (though billed as a western) series Firefly. It didn't seem to be available anywhere for the longest time, then it popped up recently as a recommendation on Disney/Hulu. Score!
The series aired in 2002, written and directed by Josh Whedon, before he went on to direct blockbuster movies. Despite strong fan support, it was abruptly cancelled after one season/14 episodes, leaving a LOT of threads hanging that were planned to be addressed in season 2. The cast did come back to make a movie, Serenity, a few years later, though set soon after the timeline of the series. I haven't yet watched that, as it seems to only be available for purchase or pay-to-stream. Just recently, there have been strong rumors of the cast reuniting again, so we'll see.
My wife is a huge fan of The Rookie. She wandered through the TV room when I was first watching Firefly, paused, and said..."That's him! That's The Rookie!" I hadn't made the connection, but the ship captain in Firefly is indeed a very young Nathan Fillion.