Superman [Clark Kent; Kal-El]; Batman [Bruce Wayne]; Captain Atom [Nathaniel Adam; Cameron Scott]; Starfire [Koriand'r; Kory Anders]; Black Lightning [Jefferson Pierce]; Katana [Tatsu Yamashiro]; Green Lantern [John Stewart]; Power Girl [Karen Starr]; Doctor Christine Gherhard (of S.T.A.R. Labs); Jonathan Kent (origin flashback); Martha Kent (origin flashback); Thomas Wayne (origin flashback); Martha Wayne (origin flashback); Metallo [John Corben] (villain); President Lex Luthor (villain); Major Force [Clifford Zmeck] (villain); Joe Chill (villain, flashback)
Synopsis
Metallo is committing crimes in both Metropolis and Gotham, meanwhile a kryptonite asteroid is on a collision course with Earth.