There's no way to tell for sure who 'them' are from just this title. It could be any group of people, like a group of friends, coworkers, or even a sports team.
If 'them prime' is a relatively unknown or new production, it might be difficult to determine off - hand what it is based on. You could try searching for it in specialized entertainment databases or forums where fans might discuss its origin if it is based on a true story.
Since I don't have a clear understanding of what 'them prime' is, I can't give examples of ones based on a true story. It could be a brand - new creation that hasn't been widely publicized or something very niche. You might need to clarify what 'them prime' actually is to get relevant examples.
I'm not sure specifically which 'them on prime' story you're referring to. There could be many shows or events with that kind of title. It might be about a group of people ('them') in a prime or important situation, perhaps in a business context, or it could be a story about a group's experience on a platform like Amazon Prime.