Upon starting this blog a couple of years ago, I wrote individual posts about the Canadian characters in the DCU. Most had only appeared a handful of times and among them, to my knowledge, Plastique is the only one to transfer over to the New 52.
She first appeared in Firestorm #7 (cover-dated December 1982). Frankly, she seemed like little more than a throwaway villain, but she resurfaced in later issue of the series (33 to 36 in a story in which the other members of her terrorist group attempted to break her out of prison). When blackmail failed to achieve the desired results, a colleague infiltrated the prison in which she was being held and injected her with a liquid that gave her the ability to cause explosions with a touch (as opposed to wearing explosives as she did previously). She used her new power to escape, and teamed with Killer Frost briefly before being captured by Firestorm again.
Her next prominent appearance was in the Captain Atom series (1987), starting in issue two. Captain Atom was drawn by Pat Broderick at the time, who had also drawn the Firestorm issue in which Plastique was introduced.
In this issue, Atom attempts to infiltrate Plastique's terrorist group. He fails, but he does manage to uncover Plastique's plans to bomb New York and Ottawa and, of course, prevent it from happening.
They faced off while on similar missions in Cambodia (working for different sides towards the same goal). Plastique was responsible for a distraction which caused Atom to be critically injured, but she also found herself in a position where her survival depended on his. While she took care of him, and he reciprocated, a relationship developed between them.
Their marriage did not last long, however, and Plastique returned to her villainous ways, usually as a member of the Suicide Squad, appearing in books such as Checkmate, Birds of Prey, Manhunter and Justice League.
She is not identified as being Canadian as such but she did display the traditional ridiculous French accent that finds its way into comics, so we assume that her background as a Québec terrorist remains regardless of how outdated it is.
I was more impressed with her appearance and degree of involvement in the Trinity War and Forever Evil storylines. In the first chapter of the former, which takes place in Justice League #22, she is anonymously sent to take Madame Xanadu out of circulation.
As the villains begin to rule, she makes the occasional cameo in the Forever Evil mini-series, but apparently she will be further involved in the ARGUS and Rogues Rebellion spin-off minis as well over the next month or two.
She's also been animated, looking rather hawt with short hair in Justice League Unlimited...