WARNING: The following contains major spoilers for Season 1 of Sweet Tooth, now streaming on Netflix.
Netflix's Sweet Tooth follows Gus, a naive 10-year-old deer-boy, as he sets out across a post-apocalyptic American prairie to find his mother, Birdie, accompanied by a pair of unlikely companions. Over the course of the eight-episode first season, viewers get a better picture of this dystopian world, even as Gus uncovers the truth about his origin -- and it's absolutely heartbreaking.
Based on the DC/Vertigo comic by Jeff Lemire, the fantasy series is set against the backdrop of twin events that occurred 10 years earlier: the outbreak of a deadly pandemic, commonly referred to as the Sick, and the unexplained births of hybrids -- babies that are part human and part animal. They were followed by the collapse of civilization, known as "The Great Crumble," and the hunting of hybrids by some humans, who viewed them as the cause of the virus. However, Gus (Christian Convery) is one of the lucky ones, raised by his father (Will Forte) in relative safety in their secluded forest home. That changes when, armed with scant clues, the boy sets out for Colorado in search of answers.
Gus' only friends are a burly loner named Jepperd (Nonso Anozie of Game of Thrones), who's trying to escape his own past, and Bear (Stefania LaVie Owen), a fierce teen activist who believed the hybrids were a miracle of nature.
However, as flashbacks eventually reveal, Gus isn't a miracle of nature but of science. Gus' father, Richard Fox, was a janitor at the Fort Smith science lab, where Birdie was geneticist. After seeing Birdie distraught at the research facility -- she was informed of her transfer -- Richard encounters her at a bar, and the two immediately hit if off. Unfortunately, however, their accidental date us interrupted, and their burgeoning relationship takes a turn.
Alerted that the U.S. military had arrived at Fort Smith to seize her work, Birdie must rely upon Richard to sneak into the facility. It's there she reveals the hybrid baby Gus (an acronym for "Genetic Unit Series 1"), which she created in a lab using a microbe discovered in Arctic ice. Her research was intended to lead to the creation of vaccines, but, as Birdie explains to Richard, it also has a dark side: "That research, and what we've been doing, will kill millions of people." (When asked in Sweet Tooth's present what the connection is between the virus and Gus, Birdie's friend and former colleague, Judy, confided, "I once heard her say they were two sides of the same coin, but she wouldn't tell me any more than that.)
As they're prepared to escape Fort Smith, Birdie begs Richard to take Gus and keep him safe, so she can go back and retrieve or destroy her research, to keep it out of the wrong hands. Richard flees with the baby, and sets off for Yellowstone National Park to carve out a haven safe from the humans who have begun to hunt hybrids. Richard assumes Birdie died, which is seemingly confirmed when Gus, Jeppard and Bear arrive at her home in Essex County, Colorado, only to find Judy living there.
Stunned to see Gus alive and well, Judy admits Birdie disappeared 10 years ago. Sadly, none of this is the origin Gus sought: Richard isn't his biological father, and Birdie isn't the biological mother he had long dreamed about. After finding Birdie's files, and proof of his creation, Gus flees the house, now more uncertain than ever about who he truly is.
Sweet Tooth stars Christian Convery, Nonso Anozie, Adeel Akhtar, Aliza Vellani, Stefania LaVie Owen, Dania Ramirez and Neil Sandilands, with Will Forte and James Brolin. Season 1 is now available on Netflix.