How to detect if an object has something over it?

I have a blueprint in which I have two objects (let’s say two cubes to make it easier). I have twu cubes one over another one like this:

74240-sin+título.png

At some point, the square that is below disappears. When that happens, I want the square that is above it to realize that the other one is not there and fall down until he touches floor.

Since now I tried this:

But it doesn’t work as expected… Any help please?

You might want to enable physics on both objects and let the gravity handle it.

On your blueprint, the line trace is going UP, but you described the upper block checks if isn’t any block below, you may want to multiply by -100 instead.