Later, during the events of "Zero Hour", Palmer is rejuvenated to a teenage state and develops the ability to grow in height in addition to his previous abilities, all of which he was capable of controlling innately without using his white dwarf star-based equipment. He becomes field leader of a new group of Teen Titans, composed of hybrids of human beings and the H'San Natall, after a chance meeting with Isaiah Crockett on his first day attending Ivy University. As a former member of the Justice League, Palmer viewed his affiliation with the Teen Titans as a step backward. The group primarily battled the Veil, an anti-alien organization that employed Deathstroke and Dark Nemesis, but it's revealed that their leader Pylon was actually a H'San Natall. They would also face Jugular (hired by the H'San Natall) and Loren Jupiter's son Jarrod, aka Haze. The Atom's new growth powers were instrumental in the battle against Sekhmet of the Millennium Giants. Ray subsequently regains his original age and memories and loses his new powers after he begins to rapidly age and Waverider has to use DNA taken prior to his rejuvenation to restore him to his original state. Palmer returns to his teaching job at Ivy University, but also becomes an associate and alternate member of the JLA. With his exit from the Teen Titans, the group disbands. One notable student under Palmer was Ronnie Raymond, who, without the knowledge of elements of Martin Stein, found difficulty in fully employing his abilities as Firestorm.