The day Big Mac came to Equestria, he was but a small colt. He told his story to passersby, but nopony believed him. Eventually, Applejack and Granny Smith found him, and brought him in. Except, they believed his story. They swore they would never tell anypony. But promises sometimes cannot be kept when you're the element of Honesty, and so the secret slips one night, and Applejack couldn't feel more guilty.