Necroscope®: The Möbius Murders

Harry Keough, aka the Necroscope, has always considered himself a master of the Mobius Continuum - a dimension existing parallel to all space and time and his personal instantaneous gateway to anywhere in the multiverse. But this is hardly overweening conceit on Harry's part, for to his knowledge he is not unique; two other intelligences, with powers similar to his, do indeed exist. One such is the long-dead August Ferdinand Mobius himself, the German astronomer, mathematician, and discoverer of the eponymous Mobius Strip which led him to explore, posthumously, his previously conjectural Continuum; and the other is Harry's son, who has not only inherited his father's mathematical skill but also the metaphysical talent by means of which the Necroscope converses with dead people in their graves! Picture Harry's confusion, then, on returning home via the Mobius Continuum from an adventure in Las Vegas, as he witnesses however briefly a flailing figure hurtling conscious but uncontrolled through the endless midnight of the Continuum.
Who could this be - how can it be? - that a helpless, silently protesting other is rushing meteor-like across the Continuum's Stygian vault? Moreover, if he hasn't arrived here voluntarily, then what vile murderer has sent his victim on this monstrous journey to the end of life itself? For Harry is sure that this is neither his son's nor Professor Mobius' doing. Who and where is he, this Mobius murderer? It is a mystery that only the Necroscope can ever hope to solve - but at what risk to his own life?