I'm gonna write a new story based on the long version of IU's 'Only I didn't know', or at least what I get from it (if you haven't seen it, here it is). 

It'll be about someone in a mental institute, and from the point of view of their lover, watching as the person they love goes crazy. 

Your advice is needed. I can't decide who to do as the characters. The person going crazy can be Taemin (paired with Key), Krystal (paired with anyone from SHINee, f(x) or SNSd except Jessica), or an SNSD member (paired with another SNSD member). 

Please let me know who you think the two main characters should be; if you have an idea apart from the ones above, please tell me that as well!

-saranghanguk