Strict, blue haired nobodies

Vexen, with Luxord and Zexion's assistance, has managed to build the world's first time machine. However, the first people to know its a success are Axel and Roxas, and that's only because they were the first to get whisked away! Demyx and Zexion are left alone, racing with the clock since it was only a matter of time the Organization found out where their friends had gone. Somehow separated from his red headed companion, Roxas will have to figure out how to get back, unless he really wants to spend 64 days all over again. Will he find out more about his future, his friends, and his purpose by living in the past?
(Just so there is no confusion, Demyx is the 'top' in this fanfiction, as that is my preference)