Card Ruling Yu-Gi-Oh for "Book of Moon"?

Alright say you summon a monster, I dunno you choose (buster blader) and the next turn your opponent equips it with a card, any card you choose (darkworld shackles, Megamorph) what would happen to the equip card if you then counter with book of moon. b/c i am pretty sure equips don't work on face down monsters. Oh and if the equip card's effect would just deactivate, then tell me if it was relinquished?