Okay kiddo, so the "Second Coming" is a poem that talks about a big event that is supposed to happen sometime in the future.
The poet, William Butler Yeats, believes that the world is not in a good place, and that it's getting worse and worse every day. He thinks that there are bad things happening all around us and that people are losing their hope and faith.
But he believes that one day there will be a big change that will come and fix everything. This change is called the "Second Coming".
Now, he isn't talking about Jesus coming back to Earth (like some people might think). Instead, he's talking about something that is much more mysterious and powerful. He describes it as a big, scary creature that is coming from somewhere far away.
The creature has the head of a lion and the body of a bird, and it is so big and scary that people can't even look at it without feeling scared. It's like the "coming" of a giant, terrible bird-lion.
When this creature finally comes, it will bring with it a lot of destruction and chaos. It will change everything in the world, and not necessarily for the better.
So the poem is basically saying that even though things seem really bad right now, there is still hope for something better in the future. But we should also be prepared for the possibility that this "Second Coming" might be really scary and dangerous.
Does that make sense, kiddo?