Comic Title: Action Comics #400
Publisher: DC (National Periodical Publications, Inc.)
Address: 909 Third Avenue, New York, NY
Cover Date: May 1971
On Sale Date: March 30, 1971 Copyright Date March 30, 1971
Source: Library of Congress, Periodicals 1971

Frequency: Monthly
Cover Price: $0.15
Page Count: 32
Editor: Murray Boltinoff

Title: "Duel of Doom"
Pages: 8

Feature(s):
Superman (of Earth-1)

Writer: Leo Dorfman
Penciller: Curt Swan
Inker: Murphy Anderson

Reprinted In:
Superman from the Thirties to the Seventies HC (1971)

Feature Character(s)

• Superman (last appearance in Action Comics #400; next appearance in Adventure Comics #406)

Guest Star(s)

• Supergirl (last appearance in Action Comics #403; next appearance in Adventure Comics #406)

Other Character(s)

• Arvor and Yllura (Kandorians; no further appearances)

Cameo Appearance(s)

• Brainiac (on a history tape)

Synopsis:
Two Kandorian students Arvor and Yllura compete during their final examinations to make a great discovery. Yllura discovers a hidden cavern in the Crystal Hills carved by a prehistoric cult known as the Torgs. Arvor creates an infra-scope which provides him with x-ray vision. However, an accident causes Arvor to become lost in the caverns. Yllura's presence has triggered a booby trap. Working together, Arvor and Yllura avoid the traps and escape the tunnel. Their success and teamwork is awarded at a graduation ceremony attended by Superman and Supergirl.