Hide when company is over. Keep your wings covered. Never speak the mysterious name "Rainbow Dash." Mum's rules keep Dee safe, but not when a scary purple unicorn shows up. One asking dangerous questions about Dee.
Rainbow Dash finds a maimed, unconscious young colt on the edge of Ponyville and rushes him to the hospital, but nopony knows who he is and something about him seems off...
Sweetie Belle magically derails a science experiment, causing her to switch bodies with Rainbow Dash. They try to masquerade as each other, but the weather team needs help and Diamond Tiara, well, is Diamond Tiara.