A ferocious monitor lizard named Kenge bites some of the members of the Lion Guard, temporarily paralyzing them. Kristofer Hivju ("Game of Thrones") guest stars as Kenge and David Oyelowo ("Selma") and Christian Slater ("Mr. Robot") recur as Scar and Ushari, respectively.
Janja, Cheezi and Chungu are in the Pride Lands, trying to steal a supply of Tikiti Melons intended for the elephants through the Dry Season. But before they can do so, the Lion Guard arrive, and quickly take back the Tikiti melons from the hyenas. After saving nearly all of them, the Guard wonder how the hyenas found the patch, but also decide that they should stick around for a while in case they return, much to Bunga's disappointment.
The hyenas return to the Outlands Volcano, where they stumble over Ushari. They start to argue, when Scar arrives to see what happened. Janja explains their situation, and Scar sees potential to break the Circle of Life by removing the melons from the Pride Lands, thus causing the elephants to become dehydrated as a result. He orders them to return, but Janja is hesitant to do so when the Lion Guard will be waiting for them. Ushari mentions having a friend who can help, but Janja assumes that they won't be any bigger than the skinks. Ushari explains to him that his friend, "Big Bad Kenge", won't disappoint them.
The hyenas return to the Pride Lands, wondering about Kenge. When he approaches, he quickly strikes fear into the heart of the hyenas. They ask how he's going to find the Lion Guard, but Kenge states that he's going to let them find him instead.
Nearby, the Lion Guard continue protecting the melons, when Ono notices a scuffle at the Watering Hole. Unable to see exactly who's behind the chaos, the Guard make their way over, where they find Kenge. When Kenge accepts their challenge, Fuli is first to get close. But after he bites her leg, Kion takes over, but is soon bitten as well. When Beshte is also the victim of a bite, the three wounded members collapse, unable to move with the afflicted leg. Bunga steps in and, when Kenge is close enough, breaks wind in his face, causing both the monitor lizard and hyenas to retreat.
With the danger gone, Ono realizes that Kenge must be a monitor lizard, who is capable of causing paralysis with one of his bites. In an attempt to heal themselves faster, they suggest that Ono check with Rafiki for a remedy that can heal their legs faster. He flies to Rafiki's Tree, where he discovers from Makini that Rafiki is away for the day. She offers to help instead, and, although she is still learning herself, she is brought back to the Lion Guard. She remembers that Ponya Flowers might be able to help heal, but has no idea what they look like. Since Ono does, he quickly locates a patch nearby, but also notices Kenge and the hyenas returning to the melons. Kion soon realizes why they were bitten, and sends Bunga and Ono to deal with them while Makini collects the flowers.
At the patch, the hyenas gather up the melons, and Janja turns to Kenge for help. Kenge quickly establishes his role as their leader, and orders them to start rolling the melons. But before they leave, Bunga and Ono arrive. Kenge orders the hyenas to leave, and Bunga calls for Ono to take care of the hyenas. Kenge makes a leap for Ono but misses thanks to Bunga leaping on the lizard's head. While Ono forces the hyenas to drop the melons, Bunga takes on Kenge.
After the two seemingly succeed in their missions, Ono lands, but is bitten by Kenge on his wing before he can fly high enough to avoid him. With his wing paralyzed, Ono is unable to keep airborne and falls to the ground. Bunga tries to strike Kenge but is also bitten on his lower half. With all of the Guard bitten, Kenge leads the hyenas away with the melons in tow. As the two worry, it is revealed that Bunga is not actually paralyzed.
Meanwhile, Makini has found the flowers, and adorned the Lion Guard with a flower crown on their heads. Since she is not entirely certain how they work, she decides to try wearing, smelling and eating the flowers, when Bunga arrives with Ono. He admits that the hyenas got away and, when the rest of the Guard fret, assures them that he can take them down himself. But since he is outnumbered, the Lion Guard ask Makini to help him. When the stakes are given to her, she agrees to try her best. After establishing their path, Kion comes up with a plan.
Makini and Bunga find the group heading through Embamba Canyon, and start to put the plan in motion. While Bunga distracts Kenge and the hyenas, Makini sneaks away and starts to reclaim the melons, hiding them behind some rocks. While she does so, Bunga continues upsetting Kenge, infuriating him by calling him little. Kenge enters a frenzy and starts chasing Bunga around the narrow space. Bunga then tricks Kenge into biting Cheezi and Chungu. But just before he accidentally bites Janja, a melon is thrown, drawing attention to Makini. She throws her Bakora Staff towards him in an attempt to keep him away, and he breaks it in his mouth.
At her call, Bunga quickly joins Makini, and calls up to Kion. With their legs (and wing) healed, the Lion Guard peer down at them. Although the hyenas want to run, the three are still facing paralysis from Kenge's bite. Not wasting any time, Kion uses the Roar of the Elders to send Kenge and the hyenas back into the Outlands. They approach Makini, who is overjoyed that the flowers worked. After checking that the melons are safe, they begin rolling them back to the patch. Bunga admits that whilst he's okay with dealing with Kenge and the hyenas alone, taking the melons back was another matter entirely, causing everyone to laugh.