Planet Comics #36 (May 1945) marks the second appearance of Mysta. As a character she is still not fully fleshed out though she is comfortably housed in an interplanetary fortress by this issue all the better to watch the universe and scan for evil. Being a super science hero was pretty common for tales of this age and it would take some time for her to settle into a role similar to contemporary comic book characters.
Mars, the troublesome God of War makes only a cameo appearance and is likely present only because his name is on the cover and to ease the transition from his adventures to Mysta. New stories featuring Mars would be discarded entirely and the character would appear only as reprinted tales in a few future issues and fanzines.
For more about Mars, go to Pappy’s Golden Age Comics Blogzine. He posted a great Mars story back in 2009 from Planet Comics #69. There is a reason that serial is much sought after by collectors.
In this issue Mysta goes up against slime-fungus, mind-controlled zombies and the evil, twisted despot Superbrain. It ends pretty much as grisly as expected.