Heartshine, Ponyville's resident heartmender, is excited to get a visit from her friend Light Shine. However, her friend comes with a request: to form a group of ponies that work for the princesses in order to work as a think tank to figure out new ways to combat the changeling threat. The Light Shine Group is soon sent across Equestria, investigating changeling behaviour and attacks, all the while searching for ways to keep their home safe.