Supergirl finds herself in a super team-up when a new superhero, The Flash, accidentally crosses dimensions and finds himself in Kara's universe. Together they have to battle Livewire and a new villainess, Silver Banshee.

To stop Non from wiping out Earth's population, Supergirl has no choice but to sacrifice her life. Before she does so, Kara says goodbye as best she can to her friends without telling them the truth and inciting a panic.