Filby Young was Dr. George Einwin's assistant, until the inventor killed himself. Filby then had to unravel the reasons for Einwin's death, and in doing so he began to use The Time Machine to explore time and discover the Time Keys. He then encountered Chronos, who had him undo a series of time paradoxes that had been created by Einwin. Once that was done, the machine returned Filby to his own time and the Time Crystals disappeared forever. ("The Time Machine: Trapped in Time")