Mastermind convinces the alien D'Jann to let him use his "substance converter" against the Challengers, after convincing D'Jann that the Challs are criminals. Mastermind changes the Challengers into a flame-man, a cloud-man, a wind-man, and a two-dimensional man. Working together the Challengers flatten Mastermind's gang, despite Cosmo acting oddly, because he is actually D'Jann's pet J'Suna. Realizing Mastermind is the true villain, D'Jann grabs back the converter and stops the criminals. D'Jann decides Cosmo's powers are more valuable on Earth and leaves him behind when he returns home.; The Challengers debate how to deal with two re-emerging volcano-men. Prof wants to use carbon dioxide foam; Ace wants to use liquid oxygen. The team splits up to pursue their own methods on the two volcano-men. Their separate attacks fail, and after the two combine volcano-men, the boys stop Rocky from making a suicidal rush. Finally they all work together. Smothered with both carbon dioxide and liquid oxygen, the Volcano Man crumbles to ash. The Challengers agree to work together from now on.