In the early hours of a 1988 morning, four girls, disparate in every way, find themselves bound together by circumstance. A peculiar object has fallen into their quiet suburb, and they must learn to rely on one another simply to endure.

Erin persuaded her older self to assist her and the other girls in finding a path back to 1988—a desperate endeavor complicated by the relentless pursuit of Prioress, an Old Watch soldier consumed by the desire to obliterate them from exist…

Mac encounters Dylan, her brother, now a man, and is taken aback by the path their family has taken. Meanwhile, Tiff, KJ, and the Erins encounter an unfamiliar individual who may hold the key to returning to the year 1988.

Perhaps Larry has devised a means for the girls to return to 1988, but it will demand a considerable effort from Erin, and Mac may find herself reluctant to rejoin her former life after her time with Dylan.

Erin, now a grown woman, undertakes a perilous journey back to 1988, a venture that takes an unforeseen turn. The girls find themselves at KJ's house, uncovering a significant secret regarding her destiny.

Driven by a fierce longing for home, Tiff guides the other girls to a version of herself grown. This older woman has achieved many of the aspirations of her youth, yet falls short of the envisioned ideal. United, they must decipher Larry's …

Tiff faces her older self, a reckoning with the paths she has taken. Meanwhile, KJ attempts to guide Mac through the complexities of her future, as Larry and Erin signal for assistance.

A strange presence settles upon Larry's farm: the Old Watch. For the Girls, it represents a single opportunity to return to the year 1988.