240 Volts - No Neutral Required - How does Power Return to Earth?
Power doesn't want to return to earth.  It wants to return to source.  

For natural power, ESD and lightning, yeah, source is earth.  However, for human power, source is the transformer or battery.  So hot wants to get back to neutral or the other hot.  

As it happens, there's an equipotential bond to keep the three voltages (240V and neutral in the middle) from getting too high compared to earth.  This bonds neutral to earth. As such, wayward current can work its way through the grounding system, the neutral-ground equipotential bond and back to neutral. But power would prefer neutral or the other hot.