Chargé d'affaires

Imagine you have a really fancy toy car that your friend borrowed from you. But your friend had to go away for a while and they couldn't return the car to you. So, they left the car with their friend who promised to take care of it until your friend comes back.

Now, the friend who took care of your car is called a "chargé d'affaires". In grown-up terms, this person is like a temporary diplomat who takes care of the affairs (or business) of their country in another country when the usual diplomat is not available.

So, the chargé d'affaires is like a babysitter for important things between two countries. They can talk to the government of the other country on behalf of their own country, and they can make decisions that are important for their country's interests. But they can only do this until the usual diplomat comes back, just like how your friend will come back to return your toy car.