120v on black and white wires
When things are plugged in to different outlets in different locations, but are all on the same circuit, from that given protective device ( breaker / fuse ) and a neutral becomes disconnected that neutral will become "hot".

Try seeing how many things you know are plugged in to that circuit if possible and you'll possibly find a few things that aren't working...

Somewhere, either behind some receptacle, or in the panel itself that neutral became disconnected. 

Envision the neutral as the return circuit for the hot ( which it is ) Whether it goes through a ceiling light, something plugged in it's still running hot as it travels through the neutral, when it becomes disconnected.