[quote=@RumikoOhara]
[@Poi]

I'm watching a narrated read of the Story. The guy who did it can ramble a bit but in that rambling he touches on the previous storyline
[/quote]

The VNs (alternative and unlimited) are technically part of the original VN. Alternative/Unlimited start off at a certain point in the Extra story line, and then they go on their own respective story lines from there.