In the two-part tale “The Secret of Volcano Mountain” of Wonder Woman #120 (Dec 1960), a meteor from Mercury delivers an “ice genie” to plague Wonder Girl. Years after defeating it, a “fire genie” is sent from Mercury to threaten Wonder Woman’s world.
Steve Trevor gets involved and is captured by the beast while Wonder Woman hears the plea from the village being threatened by the molten mountain where the genie stands. Wonder Woman realizes her duty and decides to destroy the beast (and Steve) to save the village by plugging up the mountain and trapping the creature inside, trying to put out the fire by depriving it of oxygen.
Wonder Woman is eventually successful, but alas, poor Steve must have perished with the flame beast, has he not?
Alas no, the one-note character Steve Trevor is, of course, alive and well thanks to an oxygen mask he still had in use from his airplane when he ejected.
I thought the Wonder Woman piece of this story was great (I could have done without the Wonder Girl bits). The tale definitely seems to be a leveled-up version of Wonder Woman heroics in terms of artwork and action sequences and taking her character seriously for once.