Rainbow Dash discovers that there is a pony in Ponyville who claims that she is Mare-Do-Well, even wearing the same costume. When Rainbow Dash discovers that it isn't her friends again, they try to find out who this mysterious mare is and figure out why she's playing Mare-Do-Well. Rainbow Dash is made to look bland in comparison, and with the Wonderbolts hearing about her defeat and consider retiring her after accusing her of jealousy, Rainbow Dash gets concerned that this might cost her her dream. Things get even worse when this Mare-Do-Well is revealed to be like Rainbow Dash was during the Mare-Do-Well incident: doing heroic deeds for fame and fortune. When Rainbow Dash's attempts to prove this end up with her being framed for the long disappearance of Mare-Do-Well herself, she is kicked out of the Wonderbolts for good. With Rainbow Dash leaving Ponyville in response, Twilight and her friends bring it upon themselves to discover the truth behind this Mare-Do-Well. Then they discover that Mare-Do-Well is actually a very powerful unicorn named Aurora Onyx, who was once rescued by one of the Mane Six as Mare-Do-Well, and when she discovered that Mare-Do-Well has been gone since the Mare-Do-Well Celebration and was last seen being chased by Rainbow Dash, she immediately comes to the conclusion that Rainbow Dash was so jealous, she did something horrible to Mare-Do-Well. She then left before she could discover that Mare-Do-Well was just a means to teach Rainbow Dash a lesson to get the power to take the identity of Mare-Do-Well, rescue the original, and punish Rainbow Dash for her crime, all while gaining fame and fortune along the way. When the truth is revealed to Aurora, she becomes so guilty, she tries to take it upon herself to find Rainbow Dash and apologize. But when she finally finds her, things will not be pleasant as Rainbow Dash is still bitterly angry due to the loss of her job. How will this play out?