Historium: Repairing the Timeline

After a discovery of a new hidden element called historium, scientist realizes its importance but now also face a never seen before crisis, historium has been giving humans souls but now the past has been cut off from the present and with the source situated there, humanity lost their souls and became mindless zombies, a group of lucky scientist who avoided this incident by being in a protected place will team up with an seemingly unafected man, the man assisted by the team will travel to the past in different eras and will try to fix a past that is going the wrong way... but with a twist, something very important has been changed and this might be the fault of somebody else, for what goal?