In the show, a three-person team heads out to Tasmania to see if they can find a living thylacine (also called the tasmanian tiger), a marsupial that is said to have gone extinct in 1936. However, there have been people who have reported sightings of living thylacines over the years.
The crew talked with some people who claimed to have seen living thylacines, so reports from the last few years, and take a look at some tasmanian devils, the thylacine's closest living relative. They then spend two weeks trying to spot one of the creatures.
They sat out at night (of course, you can't have a show about something unknown without searching for it at night, it's one of the rules!) They never spotted a thylacine, but saw many of Tasmania's animal species. On the last night out there, the main investigator, Forrest Galante, found a cave where he found remains of some animal that he thought looked like a thylacine kill, but the bones had been there quite a while, so whatever killed the animal was no longer in the area.
Even though a thylacine was not spotted (or heard, or recorded on a camera, or anything) in the show, I found Extinct or Alive to be one of the best cryptid documentaries I've seen in quite a while. Why is that, you ask? It's because it doesn't have parts that are totally dramatized or parts that are totally fake, like mostly all other cryptid TV shows. The show is about a search for the thylacine, and that's what you see. The only thing I didn't like about it was that whoever made it tried to make it seem like thylacines were the most dangerous thing that ever lived.
If you get a chance to watch Extinct or Alive: The Tasmanian Tiger, watch it!