Comic Title: Showcase #18
Publisher: DC (National Comics Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: Jan/Feb 1959
On Sale Date: November 18, 1958 Copyright Date November 18, 1958
Source: Library of Congress, Periodicals 1958

Frequency: Bi-monthly
Cover Price: $0.10
Page Count: 32
Editor: Julius Schwartz

Title: "Invaders from the Atom Universe"
Pages: 15

Feature(s):
Adam Strange (of Earth-1)

Writer: Gardner F. Fox
Penciller: Mike Sekowsky
Inker: Bernard Sachs

Reprinted In:
Adam Strange Archives Vol. 1 HC (2004)
Showcase Presents:Adam Strange Vol. 1 TPB (2007)
Showcase Presents:Showcase Vol. 1 TPB (2012)
Adam Strange:The Silver Age Omnibus HC (2017)

Feature Character(s)

• Adam Strange (last appearance in Showcase #17; next appearance in Showcase #18)

Supporting Character(s)

• Alanna (last appearance in Showcase #17; next appearance in Showcase #18)
• Sardath (last appearance in Showcase #17; next appearance in Mystery in Space #55)

Villain(s)

• The Vrenn (Sendal named; a sub-atomic race; no further appearances)

Other Character(s)

• The citizens of Rann (no further appearances)

Synopsis:
Adam Strange returns to Rann. He finds that all the people are missing, replaced by aliens called the Vrenn. The Vrenn use a device called the Orkinomikron to shrink Adam to sub-atomic size. Adam then finds himself in a sub-atomic world trapped with the other citizens of Rann.

Adam learns that the Vrenn originated from an even smaller world. They exhaust the world's resources, then switch places with the inhabitants of larger worlds using the Orkinomikron. Adam and Alanna locate one of the devices left behind by the Vrenn. It has enough power to restore Adam and Alanna to normal, so they go back to Rann to bring more fuel.

After retrieving the fuel, Adam and Alanna return to the sub-atomic world. They restore the inhabitants of Rann to normal. Then the Vrenn and Ranagarans battle each other, while Alanna builds another Orkinomikron on Rann. Using the device, the Vrenn are returned to the sub-atomic world, without fuel to return to Rann. Adam then returns to Earth via Zeta-Beam.