Again a special without a lot of story going on.
It's just fluffy and lovely to watch their interactions but story-wise nothing is really going on. So, if you have seen the series, it's a fluffy ending without substance. As usual a cameo of the MLs of "Stay with me" was brought into the epsisode which did also nothing for the story but it's nice to see some other couples in each other series. I would wish for a real cross-over which could be entertaining as well.
So turn your brain off and enjoy watching their interactions.