This is 'Full Circle.'
I don't need to expand on the idea of Ripleys struggle being one of keeping the Alien as far from Earth as possible. If this is canon, which it is, it makes that struggle more profound.
Shit the bed, I'm babbling. I'm actually speechless. I've waited 2 decades for this. I thought I didn't care anymore. f**k it, I was given the Anthology 2 Xmas's ago and I've not watched any of them yet. I'd seen them too many times.
It's actually happening.