Worlds Finest

"Hey, I'm Barry Allen. I'm the fastest man alive. Also, I think I am on the wrong Earth. I'm gonna need your help."

- The Flash to Supergirl

Synopsis
Kara gains a new ally when the lightning-fast superhero The Flash suddenly appears from an alternate universe and helps Kara battle Siobhan, aka Silver Banshee, and Livewire in exchange for her help in finding a way to return him home.

Protagonists

 * Super Friends
 * Supergirl (Kara Danvers)
 * James Olsen
 * Winn Schott
 * The Flash (Barry Allen)
 * Cat Grant
 * Lucy Lane

Antagonists

 * Silver Banshee (Siobhan Smythe)
 * Livewire (Leslie Willis)

Other Characters

 * Green Arrow
 * Black Canary
 * Firestorm

Teams and Organizations

 * Super Friends
 * DEO
 * CatCo Worldwide Media
 * The CW

Species

 * Kryptonians
 * Humans
 * Metahumans
 * Metahumans (Earth-1)

Objects and Concepts

 * Supergirl Suit
 * Kal-El's Blanket
 * The Flash Suit
 * Tachyon Enhancers

Locations

 * Earth-38
 * Earth
 * North America
 * United States of America
 * California
 * National City
 * Earth-1