SUPERGIRL #21 BLANK VAR ED
"Blank" Covers have an extra white card stock cover over top of the regular cover. Usually people try to find an artist to draw a special personalized cover on them!
Mourning the loss of the Kryptonians wiped out by Rogol Zaar, Supergirl decides to play detective and sets off into deep space to learn more about the would-be usurper. Using whatever tech she can scrounge, Supergirl builds a star cruiser, and after intel from Green Lantern, she blasts off into the cosmos with Rogol Zaar's deadly axe to solve the mystery-along with a traveling companion you won't believe!