Giant-Size Avengers (1974) #4

Scarlet Witch is imprisoned by the almighty Dormammu- but not if Vision can help it! The Avengers' resident synthezoid travels to the Dark Dimension to save the woman he loves. But can Vision, a creation of science, hold battle with Marvel's mightiest mystic? Vision and Scarlet Witch vs. Umar and the hellish Dormammu!