Details of the plot have remained vague thus far, but Shuler Donner was happy to tell us shed a little light on things. “We have a script on Magneto which is actually sort of Magneto and Charles Xavier,” she said. ‘It’s Eric and Charles in their early, early years.”
The site also mentions a synopsis that has been posted by Production Weekly, but that is an unconfirmed plot.
Source: Empire Online