In the dwindling hours of the twins' last day, everyone descends on Westbrook. The Breach is opened, but the climatic and bittersweet reunion leaves some descendants robbed of their escapes and others, of their lives.

In the final days of their third lifetime, Noah and Evelyn become desperate to reach Siena and Warrick, but an ancient stranger Kroden emerges and sends his son Vulcan to end their reunion and Cain's vendetta.

A turbulent end to their second lifetime, propels the twins into their final lifetime, a dystopian wasteland. Evelyn and Noah become desperate to reach Siena and Warrick, but an Ancient stranger, Kroden, emerges.

Evelyn's memory of Warrick is triggered, sparking a passionate reunion, whilst Noah and Siena celebrate their engagement. During a trip to town, the descendants come face to face with Cain and unearth the truth of his immortality.

Cain, now cursed by immortality, learns that Noah and Evelyn are among those who possess the key to return to Earth. He begins hunting them through their first lifetime, which resembles the western frontier.

A group of people "Ancients" are relocated to an alternative world. Centuries later, Cain, an Ancient cursed by immortality, learns that Evelyn and Noah are among those who possess the key to return to Earth. He begins hunting them.