Basically there's a bunch of sibling scientists and they make a time machine except they can't get the times they want to go to accurate.
So they send a guy out anyway because they're idiots and he never comes back. So they follow him. And instead of going to where the guy was supposed to go, they end up 1,000 years in the future. Apparently by now the world has already faced an apocalypse and human extinction. The place is pretty much desolate. Animals have evolved really weirdly to survive the harsh conditions.(YES LAZER COWS)
Apparently, they were also supposed to age: but by now, the world is ageless, and instead, they "evolve" too, and grow parts. They discover a substance in the atmosphere that preserves age for centuries. If they could get this back to earth they'd be billionaires: but they can't go back.
I'm kind of getting some Lost In Space vibes. You?