Doctor Joshua Champion manages to tap into another dimension and is kidnapped by the Commander, the evil overlord of that domain. Charged with the power of the Commander, Joshua manages to contact his children Ian and Victoria, and his sister Meredith. He grants them the power to resist the Commander’s intended take-over of the Earth.
The children and their aunt contact the JLA and Supergirl and transport them to Earth Two, where Joshua’s mental resistance had deflected the Commander’s efforts.
The JLA teamed up with their JSA counterparts and half stayed to defend Earth Two while the rest travelled to the Commander’s home dimension, where they managed to rescue Doctor Champion but not before falling under the spell of the Commander themselves.