Bridwell, Gill and Sparling give Crimson Dawn the focus in Secret Six 5 (Dec/Jan 68/69).
In this story, we know right off the bat that Crimson will get her opportunity for vengeance, which helps make the story more fun. The plot involves the stolen crown jewels of a European country, and the evil forces trying to overthrow the princess of that country, before her coronation. Mockingbird assigns the group to get the jewels back and prevent the overthrow of the princess.
Johnny Bright, the thief who took the jewels, is the man who married the wealthy but unattractive Crimson back in the day. He squandered her inheritance and then ran out on her, leaving her to the contempt of the remainder of her family. Mockingbird hooked her up with Lili, who transformed her into a super model.
The story is a fun one, which sees August and Lili pretend to be criminals bidding for the jewels against the other schemers from the country. Crimson gets to romance Johnny, who of course does not realize this is the same woman he seduced and betrayed.
Crimson also knows Johnny well enough to figure out that he has concealed the jewels and crown in plain sight, in the chandelier and lampshade. The jewels are retrieved, the schemers are exposed and deposed, the princess gets crowned, and Johnny goes to jail.