13: Riddle of the Sphinx - 2000AD prog 602

Schiehallion, Scotland: February 10, 1988: Zenith catches up with Michael Peyne, “I’m really angry.”
London: February 10, 1988: Peter St John is floating cross-legged three miles above the Thames, waiting for the missiles. He intends to try to catch them.
Schiehallion, Scotland: February 10, 1988: Peyne tells Zenith that he thought Zenith should have lost his powers that day, having worked out his biorhythm from his birthday. However Zenith’s real birthday wasn’t January 8 as was commonly thought - that was Elvis’ birthday - Zenith had adopted it as a publicity gimmick. Remembering the missiles, Zenith speeds off to stop Wallace, who has locked himself into his computer vault. The lock is voice activated by the answer to a riddle; one that is beyond his mental capabilities. He tries something; he attempts to talk to St John telepathically - and it works! St John tells him the answer, and he enters the vault. Wallace welcomes him in, saying that there’s four minutes left.