Secret Passages AU

Anna realizes 18-year-old Elsa is trying to attempt suicide after their parents' shipwreck, and breaks into Elsa's room to stop her. Now Anna knows about Elsa's magic since the room is covered with ice. How will this change the future? AU divergence from my story Secret Passages from chapter 23 onward. (Can be read alone, but may reference previous events from Secret Passages.)