...to be blunt, they were about to die, either covered in lava, or hurled into the void when the alien world they're on is hit by a wandering planet!
This never-reprinted tale by writer Frances Crandall and
artist Fran Matera from Treasure Chest V14N18 (1959) winds up the the serialized storyline.
Though these characters never reappeared, Treasure Chest continued to do sci-fi/fantasy serials until the book was cancelled in 1972...after publishing over 500 issues!