Darmok is a story from a TV show where there are creatures called Tamarians who communicate in a very different way than humans do. They use stories and metaphors instead of just straightforward words.
So, for example, if a Tamarian wanted to say "let's work together," they might tell a story about two warriors who joined forces to defeat a great enemy.
The problem is, the humans on the show didn't understand the Tamarians' way of communicating. They would hear the stories and not know what they were supposed to do.
This caused a lot of confusion and frustration, but eventually, the humans and Tamarians were able to figure out how to communicate better with each other.
In summary, Darmok is a story about the challenges of communicating with people who have very different ways of expressing themselves.