Intergalactic Choices

Two alien races are at war. For survival the Zendranians must leave their galaxy and find another planet to inhabit or they will be annihilated by the vicious predatory Meethra who are killing them off at an alarming rate. Can Zendranians safely assimilate into the human race? To find out they convince two Earthlings an engaged couple to time travel through their ancestral lines to significant historical events their descendants lived through. This will allow the Zendranians to evaluate the choices humankind makes and how those choices affect future generations to determine if Earth will accept intergalactic beings. However they must hurry--time is of the essence.