In this series, Kara meets her Earth doppelganger named Karen Starr, like Clark's doppelganger Hank Henshaw. She is the daughter of a wealthy and successful businesswoman who owns "Starr Enterprises", but she doesn't give her the time of day. Karen is a huge fan of Supergirl and dreams to be just like her someday, and she soon gets her wish.
Within the ship Superman came to Earth from is a Krypton data matrix called the "Codex" that contains the biology and DNA of the Kryptonian species. Lex Luthor discovers it hidden in one of Amanda Waller's hideouts and attempts to use it against the heroes. But Karen steps into the fray and stops his plans, but due to an accident the Codex's data is downloaded into her.
Karen wakes up the next day to discover she has Kryptonian superpowers like her idol and becomes the superheroine she dubs Power Girl. At some point she gets infected by Star Conqueror spore and gains additional powers.
Here are the powers of Power Girl:
Kryptonian Physiology:
Superhuman Strength
Superhuman Speed
Superhuman Stamina
Superhuman Durability
Superhuman Hearing
Superhuman Breath
Superhuman Vision
X-Ray Vision
Flight
Heat Vision
Solar Energy Absorption
Star Conqueror Spore Enhancement
Telepathy
Psychic Link
Astral Projection
Phoenix-like Form
Pyrokinesis
Fire Wings
Claws