Okay, so let me explain "Das Kapital" to you like you're five.
Have you ever had a toy that you really like to play with, but your friend wants to play with it too? But you don't want to share your toy because you're worried your friend might break it or not take care of it properly?
Well, that's kind of what "Das Kapital" is all about. Instead of a toy, it's about things called "capital" that some people have a lot of, and others don't have as much.
Now, what is capital? Capital is basically any resource that people use to make things or provide services. For example, factories, machines, and money are all forms of capital.
Some people have a lot of capital, because they inherited it from their parents, or because they were able to make a lot of money themselves. Other people don't have as much capital, and have to work for other people who do.
Now, the person who has a lot of capital can use it to make even more money by charging other people to use their resources. So, someone who owns a factory might charge people to make things there, and the person who owns a lot of money might lend it to other people and charge them interest.
Karl Marx, the guy who wrote "Das Kapital," said that this system isn't fair. He said that the people who have a lot of capital are able to exploit the people who don't have as much, by making them work for lower wages or charging them more to use their resources.
Marx thought that this system needed to change, so that everyone could be treated more fairly. He believed in a system called socialism, which would put the resources of society in the hands of everyone equally, instead of just a few wealthy people.
So, in summary, "Das Kapital" is a book about how some people have a lot of resources called capital, and can use it to make more money at the expense of other people. It was written by a guy named Karl Marx, who wanted to create a more fair system where everyone has equal access to resources.