[She tries responding to her first through the journal - figuring that would be how Elsa would want to be contacted first, after all. But when enough time passes without her answering, Sakura will set out to find her.
which is. easy enough to just follow the trail of ice towards the giant, very subtle castle of ice. Yes.]
[She does knock, at least, even though it's a bit odd to knock on ice (sorry, water-kun), and she's opening the door anyway after a moment, calling out]