Twilight is not, under any uncertain circumstances, a morning pony. When her mailmare drops by to give her the mail, she does not usually smile, much less invite her in for breakfast. But Derpy is different. Twilight doesn't know how, or why, but being with Derpy always makes her smile, no matter the time of day. After a baking accident lights Twilight's house on fire, where does she stay? With Derpy, of course. TwiDerp and SpikiDink.
Rated teen for some adult themes. No clop, duh, but some situations... well. Also, some future scenes may lead to clop, but not depict it, If anyone wants to write those scenes, go ahead.