A scientist creates a time machine and kills their younger self to see what would happen. And that self-obsessed, misanthrope, mad genius of a scientist is Tim Travers. And the universe was bad enough with only one of him.
But 9-1-1 could get another spinoff on ABC in a new location, with Las Vegas among potential cities rumored to follow Los Angeles (9-1-1) and Austin (9-1-1 Lone Star).