Not too much to say... basically recap of the previous season. It's only useful if you've watched the first part of Alicization when it first aired and need a refresher before the second season begins. If you haven't watched the first part then this is no replacement, you need to watch the first part to know what's going on. If you've just finished watching the first part and it's still fresh then you don't need to bother with this, it's just a recap and is not intended to further the plot. Just skip it and move on to War of Underworld.