Following the events of Sonic the Hedgehog 2, the warrior echidna Knuckles finds himself struggling to adapt to a quiet, suburban life in the town of Green Hills, Montana. Living with the Wachowski family, his rigid warrior instincts cause chaos during a home renovation, leading his guardian Maddie to ground him. As he grapples with his purpose in this peaceful world, he receives spiritual guidance from the ghost of his ancestor, the echidna elder Pachacamac, who advises him to find a new mission by taking on a protégé.

That protégé becomes Wade Whipple, the well-meaning but bumbling deputy sheriff of Green Hills. Recently kicked off his bowling team, Wade dreams of competing in a major tournament in Reno, Nevada, where his estranged and legendary champion father, Pistol Pete, will also be playing. Knuckles decides that training Wade for this tournament is his new warrior's quest, and the two set off on a road trip across the American West.

Unbeknownst to them, they are being hunted. A mysterious figure known only as the Buyer, a former underling of the defeated Doctor Robotnik, seeks to harness the extraterrestrial power of Knuckles’ quills. He deploys two corrupt G.U.N. agents, the bickering duo Mason and Willoughby, equipped with advanced weaponry, to capture the echidna.

The journey to Reno becomes a transformative experience for both. Knuckles is forced to navigate human customs and family dynamics when the fugitive pair hides out at Wade’s childhood home in Boise, Idaho. There, they reunite with Wade’s overbearing mother Wendy and his immature FBI agent sister Wanda, leading to a chaotic Shabbat dinner that becomes a bonding experience for Knuckles and the family. The series tests the duo’s friendship as they face various threats, including a creepy former bowling teammate turned bounty hunter. In a musical dream sequence, Wade undergoes a spiritual trial where Pachacamac teaches him that a warrior’s greatest strength is their heart.

Upon reaching Reno, Wade reconciles with his arrogant father Pistol Pete, only to discover that Pete has allied with Mason and Willoughby to trap Knuckles. Wade cleverly tips off his mentor, leading to a final confrontation. While Wade faces his father in the championship match, Knuckles battles the Buyer, who arrives in a giant mech suit. The Buyer drains Knuckles of his power, but Wade, having found his own courage, stands up to the villain long enough for Knuckles to reclaim his strength and destroy the mech. With the day saved, Wade defeats his father in a perfect game, finally earning his self-respect, while Knuckles accepts his new role not just as a warrior, but as a friend and protector of his new family.