Shortly after Wonder Woman finds out that Gen. Darnell is secretly in love with her, she learns that Steve Trevor, in Darnell's words, "recklessly went out to test a new super rocket plane which killed a test pilot who took his place while he was recovering!" Steve also fails to return, and Wonder Woman's searching reveals no trace of him or his plane. Wonder Woman grieves, but Darnell consoles her, and she finally accepts a proposal of marriage from the general. However, she is unable to say the words "I do" at the ceremony, still thinking of Steve, and Darnell releases her from their engagement. The Amazon princess rescues another pilot testing the rocket plane and takes his place, finding the craft captured by rays fired from a submarine. She then battles frogmen from the sub.