Leader Jr. is the the biological son of The Leader. He has all his intellect but none of his evil. He was adopted by the Hulk, who he considered his true father. Together he teamed up with RJ3 and the Gamma Twins Betts Ross and Thad Ross to battle the "new" leader L.E.A.D.E.R.
Finally catching up to The Leader in the present, Hulk reunites with the Agents of S.M.A.S.H. However, he's unexpectedly whisked into the future by teenage Smashers who battle the Leader's threats.