Ledger Line is an accountant, and a unicorn at that. He can't grow a thing to save his life, which is bad because he's currently the owner of Cherry Jubilee's cherry orchard, and it's drowning in debt.
Enter Applejack. Applejack is an earth pony, not so good with numbers but definitely good at working in an orchard. She doesn't talk about herself much, but he's not about to question his only hope for saving the orchard. Things like her constant recurring nightmares and that hawk she always carries can stay, along with her cherry pies and business sense, if he's got any hope for saving the orchard.
If you've ever seen Ladyhawke, you know where this is going.