I’ll be honest: I’m not sure that this issue is part of the Marvel 616, but since it includes members of the Howling Commandos and because Dominic Fortune later appears in some mainstream books, I’m covering it. It takes place right before WWII, during which time Dum Dum Dugan apparently owned a circus(!) that employed Dominic Fortune as an acrobat.
That’s really all you need to know about this issue. I mean, there’s drama where Dugan loses the circus in a poker game and then has to get it back, Fortune helps him, and the circus employs a genuine psychic, but really the main thing about this story is that Dum Dum owned a circus.
Credits are a little complicated: Len Wein (plot), David Michelinie (script), Howard Chaykin (plot and layouts), Terry Austin (finishes)