How's it being the last blank flank in town, apart from a pair of ulta-annoying twins? It's annoying, it's frustrating and it's draining to come up with new ways to find your special talent, especially if the thing everypony thought was going to be yours turns out not to be.
Well, Apple Bloom has enough of her miserable existence and decides to head off into the Everfree Forest, trying to get a cutie mark in finding something she hopes she doesn't expect. For what would make a better Cutie Mark than the unknown?
Nothing goes wrong, except a lot of things, possibly everything.