Rainbow, by swerve of chance, witnesses something that she doesn't expect from Derpy Hooves, Ponyville mailmare with crooked eyes but a heart of gold. She decides to foster Derpy's new skill that went unnoticed even by the mailmare herself. In the process Rainbow learns about Derpy's real life, secret, occluded, happening outside the office and her trips, and finds herself slowly but surely falling into that most blissful and happiest of all feelings: love.