The bow on top of A Gift of Wings, additional scenes, deleted scenes, and alternate scenes that don't fit into the main story. None of it is strictly necessary for the main story, and is simply there to make it look prettier.

A pair of Night Furies hatch under mysterious circumstances into a big, wild world, unknowingly embarking on a perilous and fateful path fraught with malicious and greedy humans. Changing the world was never going to be easy, but that's what it means to become a hero the hard way.