Carthan, banished from his home world Dryanna to Earth by his ruler Xandor, attempts to contact the Justice League for help but cannot do so directly; he activates three machines of destruction that hold him to Earth and takes Green Arrow hostage, hoping that the Justice League can deactivate the machines and free him.
This issue reprints three former issues of the Justice League of America where Green Arrow, Atom and Hawkman join the League.
Story 1: Doom Of The Star Diamond - Green Arrow is recruited JLA# 4
Story 2: Menace Of The "Atom" Bomb! - Atom is recruited
Story 3: Riddle Of The Runaway Room - Hawkman is recruited JLA #31