X-Men: True Friends #1

In an adventure set back in their days in Excalibur, Kitty Pryde and Rachel Summers (a.k.a. Phoenix) are caught in a temporal vortex and flung back to 1936 Scotland, where they stumble upon a Nazi plot to destroy the British monarchy! Oh, and did we mention that they run into the mutant who will one day become the sinister Shadow King?! Ultimately, Kitty must confront the most terrible of moral choices: should she take action to prevent the Holocaust even though she knows that by doing so she may well destroy the future she came from?!