Calculator comes back to Gotham City to get his revenge on Oracle once and for all, but Barbara has her own plans, feeling as if the identity of Oracle has become too public within the Super Hero/Villain community. The solution? It is time for Oracle to disappear.
What Barbara doesn't plan for is Calculator's recruitment of a new villainess, Mortis, who is able to make her victims face their every regret in life with a single touch. During Calculator's initial attack on the Birds of Prey, Mortis is able to take Black Canary out of commission while Huntress, Lady Blackhawk and Dove are captured.
While Calculator is interrogating Huntress, Lady Blackhawk and Dove as to the identity of Oracle, he manages to shoot down a helicopter which he believes to be piloted by Oracle, thinking his has finally killed Oracle once and for all. But with the help of Batman (Bruce Wayne,) Hawk, and Black Canary, who managed to free herself from Mortis' control, the Huntress and the others are freed, and take down Calculator.
The next day, Oracle's calls go unanswered, and the underground believe Oracle to be dead, but Barbara Gordon is safe and sound in Kord Tower as she explains to the likes of both Batmen, Bruce Wayne and Dick Grayson, Red Robin, Batgirl, and Misfit her reasoning for taking Oracle underground, only allowing a very select few people outside of the Birds of Prey, to have access to her. Though she plans not to interact directly with most of remander of the Super Hero community, she explains, "Big Sister is watching everyone."