During a trip to the Crystal Empire with his girlfriend, Big Macintosh ends up stumbling upon what appears to be King Sombra's broken off horn. What surprises him is that the horn appears to be sentient and attaches itself to Big Mac's forehead, causing Sombra's lack of a heart to fuse with Big Mac's Pure Heart.
With this, the two end up merging into one being, Midnight Macintosh, lacking Big Mac's pure heart but not the heartless monster Sombra was. Midnight Macintosh does not know anything about his past two lives and has no memory of anything, he simply wanders around looking for a purpose.
He eventually meets a blue unicorn ho is aspiring to be a producer and agrees to help him with a film project, but is someone who is not heartless or lacking a pure heart cut out for what that would bring him?
(Big thanks to the user named blue-hart, this whole story idea was his! I don't get requests much so this is a challenge to write but I'm excited to work on it. If you have any questions feel free to ask blue-hart, he's a really nice guy!)