Challengers of the Unknown by Jack Kirby #[nn]

Synopsis

Four heroes are being flown to appear on the radio show "Heroes" when their jet crashes in a storm. Miraculously, all four survive unharmed, even down to a working watch. Since they are "living on borrowed time", they vow to make the best use of it, taking risks to benefit others, challenging the unknown. In their first official case, they are summoned by Morelian, a descendant of Merlin, to open four chambers of a dangerous alchemist's box and "witness things not seen on this Earth since the dawn of Man!"