Players are intended to watch Chapter 62 of the main story before watching the story for this card. I have not been following the main story, but from what I learned from other sources, I believe the events are connected to Haruka moving overseas, resulting in her leaving the main cast and Ortensia going on hiatus indefinitely. This is because her current voice actress at the time was about to retire. Basically, this is Haruka's farewell party.
The absolute tonal whiplash between this and the 4*s makes me laugh. It took the decimation of Mizuki's perception for Mafuyu to come out with the happiest card in a set.
The daisy she's holding is meant to look like an eye (you know, for the implication the song's singer ripped his eyes out). I'm adding the symbolism tag
Doesn't matter even if you say it in an obscure foreign language encrypted with a 256-bit cipher, Dia will still instinctively know you're dissing Sega from halfway across the world.