No, this sounds like a plot for a Bioware game.
The premise, as I imagine it, would be something like this:
The Russian far east was sparsely nuked, giving rise to the
Old Believers, used to harsh life in the Taiga. Much like the Mormons in the US, they preserved their religion and spread their rule to the entire far east in a matter of decades, waging a civil war with what was left of the communist authorities. Facing imminent defeat, many party members and their families fled to Alaska and east Canada, scraping by until they discovered some local vaults. Having conquered them, they remained sealed in for over a century, preparing to dominate the land when the time is right. The time became right a while ago, and the Red Army was unleashed upon the land, establishing a communist republic from Juneau to Anchorage and once again entering a waiting period, preparing for the next expansion. The time for that expansion is now, and Stalin is the one intent on carrying it out.
Vancouver was gripped by civil war between the various ethnicities inhabiting it by 2077. Having been prepared for war to begin with, the Jihadists gained the upper hand over the east Asians and the handful of Canadians that were left. The caliphate soon controlled all of Vancouver island. Ignoring the radiation, many inhabitants were affected by mutations.
But there was a secret the Caliphate was unaware of in Vancouver. When the nukes started flying, it was being visited by the pope, who along with the key figures and staff of the Vatican, took cover in a secret vault. They kept the Vatican alive for centuries, but now the last isolationist pope has died. The two pretendents to the throne of Saint Peter both claim it is time to leave the vault, but while one wishes to form an uneasy alliance with Stalin to obliterate the heathens, the other wants to go out and wash their feet.
