In an altered timeline, Na'kuhl agents led by Vosk gave technology to Nazi Germany, creating a 1944 in which German forces occupied the eastern United States.
Vosk, a Na'kuhl from the far future, fled into the twentieth century and offered advanced technology to Nazi Germany in exchange for help building a way to return to his own time. His interference, which began with the murder of Lenin in 1916, created a history in which German forces occupied much of the eastern United States.
Enterprise was thrown into this altered past after the Xindi conflict. With help from American resistance fighters, Archer infiltrated Vosk's base, and Enterprise destroyed his temporal conduit. History was restored, and the Temporal Cold War came to an end.