The Morthren have developed a time machine. Malzor travels back to 1953 to inject his invading predecessors with an immunity drug to Earth's bacteria so they'll complete their original mission of obliterating mankind and colonizing the planet. Blackwood and Kinkaid arrive at the alien's research facility and follow Malzor into the past to try and stop him.

A revolutionary "med cell" is created that could save countless lives. But fearing that the Morthrens could turn it into something deadly, the Blackwood team tries to get their hands on it first. Meanwhile, Malzor desperately tries to acquire it to heal a dying Mana, his second-in-command.