At least, that’s what he thinks. His life is mundane enough that it takes him a while to notice the days repeating. So he tells Elise. She doesn’t believe him, but she helps him anyway. With her encouragement, he finds a way out.
That’s the surface.
Watch it again and the loop starts to come apart. I’m not convinced it was ever a loop. Clues are planted early and they aren’t obvious. You’ll finish the second viewing holding a theory you didn’t have after the first. You might not be any more certain.
I love these kinds of videos.