Okay kiddo, so there are two countries called Canada and the United States that are both next to the ocean. In the ocean, there are lobsters, which are yummy seafood that people like to eat.
Now, the problem is that both Canada and the United States want to catch those lobsters and sell them to people. But there is a specific area in the ocean called the Gray Zone which is where the lobsters live, and it's not clear who owns it.
So, both Canada and the United States are claiming that they own that area, and they are trying to catch lobsters from there. But when they do that, they sometimes catch lobsters that are too small, which means they haven't had a chance to grow up and make more lobsters.
That's not good because if too many small lobsters are caught, there might not be enough lobsters left in the future. Also, some lobsters might cross the imaginary line between the two countries, and that causes fights because each country wants to protect their own lobsters.
So, that's why it's called the "Lobster War." It's not a real war with weapons, but it's a disagreement between two countries over who owns the lobsters in that area of the ocean.