"In the desperate search for Melody Pond, the TARDIS crash lands in 1930s Berlin, bringing the Doctor face to face with the greatest war criminal in the Universe. And Hitler. The Doctor must teach his adversaries that time travel has responsibilities - and in so doing, learns a harsh lesson in the cruellest warfare of all"
I grabbed this from a "Who" FB page. If anyone knows the original source feel free to let us know via the comments below.
Doctor Who returns this Fall with episode 8 "Let's Kill Hitler."