The girls subsequently chase the group to a construction house and find what appears to be a time machine in the basement.

The girls learn that the teenagers are time travelers from the distant future, who are engaged in an ongoing war with a group known as the "Old-Timers" (known as "The Battle of the Ages").

Throughout the series, the girls are frequently (and usually, inadvertently) time-displaced, traveling between the 20th and 21st centuries, as well as eras of the distant past and future.

When Clone Erin (first generation) scatters the girls to separate past/present timelines, she causes the Old-Timers to become stuck inside the fourth dimension.

[19] At some unknown point in time, a small group of clones and 2000-Tiffany gain the ability to transmit coded messages to the paper girls in the past via bizarre dreams.

[5] This group of clones and 2000-Tiffany help to end the war by convincing Grand Father to ban all time travel forever, believing such power should never be abused again.

[30] Laura Hudson from Slate stated that the series "is a reminder of how fresh and accessible even the most familiar stories and tropes can feel when people who have been consigned to the sidelines of popular entertainment take center stage".

[31] Steven Padnick from Tor noted that "the real emotional theme of Paper Girls comes to the fore: the contrast between children’s fantastic hopes for adulthood and the disappointing banality of reality" and "[the series] is glorious and moving, and also awkward and funny".

[32] The writing and artwork have been consistently praised: "Paper Girls' vivid color palette and Chiang's unique drawing style beautifully complement Vaughan's creative time-bending storyline".

"[34] Abad-Santos also praised the creative team, saying "Vaughan's writing and Chiang's art—along with colors from Matt Wilson and letters from Jared K. Fletcher—all make for one gorgeous mystery.

[34] Susana Polo for Polygon stated in her review of the comic series that "if you're a fan of Stranger Things but wish the show handled its female characters, or its queer coding, or its rosy-eyed love of 1980s pop culture with a little more nuance more frequently, you'll find a lot to like".

[36] While comparing Paper Girls to Stranger Things and Super 8, Glen Weldon stated that Paper Girls "tell[s] its story from the point of view of young women, not boys, and it doesn't seem coincidental that its tone is harder, flintier, funnier, more pragmatic, and far less concerned with idealizing the "lost innocence" of childhood.

[39] On April 26, 2021, Deadline reported that Sofia Rosinsky, Camryn Jones, Riley Lai Nelet and Fina Strazza were cast as Mac Coyle, Tiffany Quilkin, Erin Tieng and KJ Bradman respectively.

Creator Brian K. Vaughan, talking about the creation of the series, stated that "Cliff Chiang and I wanted to do a story about kids from the 20th century confronting their adult selves in the future that’s nothing like Marty McFly's world of flying cars and (actual) hoverboards, but a future that's equally amazing and terrifying for many different reasons.

They're these sorts of hard-core gangsters that are much more interested in going around, shaking down the adults who owe them money so they can get their cassettes or buy their own Nintendo systems.

Additionally, a compendium edition was released titled "Paper Girls: The Complete Story", collecting all 30 issues in one trade paperback.