Storywise this episode was a waste of time. It had some silly moments, some fluffy moments but not much substance. I felt bored and the childish behaviour of "Liu Li" was a downer for me.
So, just see it as fan-service, even the appearance of the MLs of "You Are Mine" did not much for me. If you don't watch it, you won't miss anything. I would recommand to watch the special of "You Are Mine" which completes the series in a way better way.