Vitamin C
I was not expecting to like this issue as much but it sort of falls under the maxim of "not being sure where I was going, until I got to where I wanted to be." There has been some mediocrity to this point in the series, but here pretty much every note is hit and perfectly. The battle is somewhat generic and while the action does seem like it could be in any comic, the context of it is not. There are a few things happening here at once - Kara discovering the full scope of her power, Kara deciding to make a stand and deciding that Earth is her new home - but perhaps the best part about all of this is that it is happening with any interference from her cousin. Instead of being inspired by him which has been a staple of the character's other versions, here she finds her way to heroism all by herself (and actually has not ever really been called Supergirl yet). The resolution of the story here feels like the introduction to the character is over and that the series can get on from here, but this gives it a lot of momentum as it joins the rest of DC continuity.