The Avengers (vol 1) #36 G/VG

(Story continues from last issue) Captain America is surprised to find the Scarlet Witch in Avengers Mansion. She relates that Quicksilver has been kidnapped by a UFO.  Elsewhere, Hawkeye nominates the Black Widow for membership, but Goliath objects on the grounds that the Avengers is not a "halfway house" for reformed criminals. A distress signal reaches the team. Despite Wanda's concern for her brother, Cap states that the Avengers must always concern themselves with innocent civilians first. Thus the Avengers (including the Scarlet Witch and the Black Widow) fly to the Balkans. There, they discover a huge computer named Ixar draining information from the village's Burgomeister.  Ixar lured the Avengers to him in order to extract power use them to build the Ultroids. They also discover that the Scarlet Witch who accompanied them is a fake, she is in fact an Ultroid known as Ultrana.  Ultrana and the Ultroids attack the Avengers, capturing them all. They are to be subjected to Ixar's experiments. Since the Black Widow is not an Avenger, she is sent to be destroyed.