There is a very developed planet on the other side of the universe. Their technology and cognition are far beyond other intelligent creatures. They have discovered that there is a universe outside the universe. The universe you are in is not the only one, but you have not been able to find a way out. During the mission, you accidentally bumped into the earth 2 billion years ago. . . .
Concept: What did the Earth look like 2 billion years ago?