One nice day, Ditzy Doo (or Derpy Hooves to her friends) was walking along in a marketplace when there was a terrible accident! A large cart had crashed into the poor pegasus. The mare went to the hospital with an extreme concussion and terrible amnesia. If a pony can't remember their place in society and who they are, what happens? Ditzy Doo's cutie-mark fades away along with the mare's memory. Her friends must help her remember and bring back her cutie-mark and what it means, but what do bubbles have to do with being a mail mare? Where will this lead Derpy Hooves and her friends?