The on-sale date is from the publication date recorded in the Catalog of Copyright Entries, Third Series, Vol. 1, Part 2, Nos. 1&2, Periodicals, 1946-1947.
Mysta of the Moon; Villain: Dr. Grey (intro; death)
Synopsis
When Mysta forbids Dr. Grey from continuing his atomic research, he defies her. However, an accidental explosion renders him radioactive and he plans to use his new power to kill Mysta and destroy the moon.