I am completely lost on the story...(2.7+, spoilers)

So I'm starting Sundays story as I haven't had time to play since the Wardance Arc.

And I am confused as fuck. We're wondering around, tuning things? Tingyun just appeared with no setup...it's confusing. Her reveal as being alive is the first time we're with Sunday? We're transporting here and no reaction by the Express Crew to her being alive?

Totally lost for the first time playing this.