I just completed the "Captured Memories" mission last night.
There's a slow and short theme music by piano at the after video.
After search for a while, I got the name finally.
It's called "Zelda's Wish" in The Legend of Zelda: Breath of the Wild OST.
it is only 39 sec. long.
Wonder if anyone here could arrange and share this short piece sheet PLEASE.
Video (music start form 03:00)