Supergirl first season has been good so far. It has been villain after villain, bringing Supergirl to fight against classic villains such as Supergirl Bizzaro and Red Tornado, with a twist to the story of course.
None of the story compares to the just recently introduced Indigo, or Brainiac 8, the 8th reincarnation of Brainiac. And the return of Laura Vandervoort as Indigo. Of course, in Smallville, Laura Vandervoort was Supergirl.
Indigo not only makes an appearance, but manipulates her old flame to her end, culminating in a rescue by Supergirl.