Question about an NPC questline in the DLC (spoilers)

SPOILERS FOR MID DLC CONTENT BELOW-----

So, I got a message saying that Miquella's rune has faded. Needle Knight Leda has begun saying some rather bloodthirsty things. She plans to go after the hornsent.

Without spoiling the rest of the questline, can someone tell me if I'll have an explicit choice when it comes time to make some important decisions regarding Leda, or is this a quest line in which I have to act pre-emptively in order to save the hornsent?

Basically- will I be told when it's time to act? Or if I let things progress will Leda do something that I'm unable to intervene in?