The cover image on Shazam! 16 (Jan/Feb 75) makes it look like Captain Marvel will be fighting all the Seven Deadly Sins in this issue. While that does happen, it is in one of the reprint stories. This issue collects seven other stories though, each of which plays off of one of the seven sins, with the two new stories specifically designed to do so.
Maggin and Schaffenberger open the issue with a tale in which an old foe of Captain Marvel, Professor Thorne, creates a statue of Injustice and places it in front of the courthouse. The statue gives off vibrations that affect the judge, who seems to be the only judge in town. He begins making horrible decisions in the cases that he tries. Freddy Freeman cameos as he draws Billy Batson's attention to the situation.
Captain Marvel tries to get rid of the statue, but discovers that it will set off an earthquake that will destroy the city if it gets moved.
Poking around in the prison, Billy manages to find the plans for the statue, and discovers that it has a weak spot. He throws a hammer and shatters the statue, then brings Thorne in for real justice.
Mary Marvel's story deals with envy, and is narrated by a cat. The Bridwell and Oskner centres on a young woman who is clearly very full of herself, and envious of the attention that Mary Marvel receives.
Both she and her boyfriend wind up kidnapped by hoods. The cat is some help in getting her free, but the couple wind up trapped in a cave in.
Mary Marvel saves her life and rounds up the bad guys, and the girl decides she really shouldn't be nasty to the woman who saved her life. In a nice ending, we discover that the cat has been telling this story to Mr. Tawky Tawny.
This is also the last new Mary Marvel back-up story.