Defenders (1972) #5
"World Without End?" is written by Steve Englehart with art by Sal Buscema and Frank McLaughlin. Welcome to the Defenders, Valkyrie, now get lost! That's the way the newest recruit to America's super-hero non-team feels she's being treated. With no memory of herself or that of Barbara Norris mortal body she inhabits thanks to the Enchantress' magic, the Valkyrie walks alone among the innocents she's sworn to protect. Doctor Strange, the mystic master who has offered her the shelter of his home, suggests she seek out her teammates to try to win their friendship.
Guided by crystals attuned to their unique energies, Valkyrie seeks out first the Sub-Mariner and then the Hulk. But in each case, her fellow Defenders mysteriously disappear before her eyes. With Namor's young cousin Namorita following along, the she-warrior tracks her comrades in arms to a lonely lighthouse on the New England coast. There, she finds Namor and the Hulk under the hypnotic spell of the Omegatron, a machine built by the extra-dimensional scientist named Yandroth. Now, Valkyrie and 'Nita must defeat two of Earth's most powerful beings to stop the world from ending!