Twilight Sparkle and her friends have just won a difficult struggle against an archmage scientist who had gone mad to rescue the Solaris Tear jewel, an ancient memento of a father’s love. Unfortunately, Rainbow Dash is forced to suffer from the aftermath of their battle. While at first it looked like she had gotten away without any serious visible wounds, Rainbow and her friends soon discover that not all wounds can be seen. Some wounds can be invisible to a keen eye but still bear large bleeding gaps in the pony's soul.

Blaming herself for Rainbow's terrible injury, Twilight searches for a way to help her friend. Can she find a way to treat this strange kind of wound? And... at what cost?