Published Jul 1971 by DC.
Cover by Neal Adams. "This Hostage Must Die!", script by Leo Dorfman, pencils by Curt Swan, inks by Murphy Anderson; Superman discovers that the red jewel is drawing energy from a red sun, and frees himself by blocking out its light; Then he discovers that Frank Haldane has found the treasure of Montezuma, and is attempting to steal it with a mechanical mole of his own design. "Feud of the Titans!", script by Leo Dorfman (as Geoff Browne), pencils by Curt Swan, inks by Murphy Anderson; Superman and Supergirl are made hostile to each other and goaded into a super-feud when fumes from a brainwash bomb they are disposing of in the Fortress of Solitude's disintegration pit combine with Kryptonian elements there and make them hate each other. 36 Pages, Full Color. Cover price $0.15.