While escaping a fire, Kion, Kiara, Tiifu, Zuri and Bunga must navigate through a network of underground tunnels and meet an adorable golden mole with a sweet singing voice named Kuchimba.
AJ McLean (Backstreet Boys) guest stars as Kuchimba, the golden mole.
The Lion Guard dash towards Pride Rock, having heard the distressed cries from Tiifu and Zuri. When they arrive, they discover the two cubs are upset over their physical appearance, which has been brought on by the Dry Season. Kiara and Nala arrive and scold the pair for calling the Lion Guard to a non-emergency.
Beshte suggests that the girls try the hot mud pots at the edge of the Pride Lands to moisten their fur. They agree and suggest that Kiara join them since they rarely get to see her due to her Royal Family duties, as well as her fur looking a bit frizzy. Kiara asks her mother if she can go, to which she agrees, provided that Kion accompanies them.
Bunga offers to come along as well, and the group leaves. The group arrives at the mud pots There, after Bunga convinces Kion to take a break from watching for Scar, the two proceed to splash around while Zuri and Tiifu relax. Kiara takes turns at both activities, until an angry Muhangus emerges from a den, demanding that they keep the noise down. They apologize, and Kiara returns to her friends while her bother continues playing with Bunga. From a rock above, Shupavu and Njano watch the group for a short while before sneaking away.
They return to the Outlands Volcano, reporting their findings back to Scar. They explain how the area is filled with dry flowers and mud, and how easy it would be to start a fire all around. Scar orders Njano to fetch him a vulture, who will be delivering a gift of fire to Kion and his companions.
Back at the mud pots, Bunga has joined the girls in their relaxing spa, while Kion looks out. Mzingo flies above carrying two flame-covered sticks in his talons, but Kion only hears a faint noise. He suggests that they leave, but the cubs wish to stay. Mzingo proceeds to drop the two sticks, starting a blaze on all sides of the area. Kion orders the girls to enter the mud pots while he and Bunga work on a fire break, but Kiara stays to help. However, they soon notice that the fire break isn't going to work. Kion quickly orders everyone to enter Muhangus' burrow, but Tiifu falters. She eventually enters the burrow with everyone else, safe from the blaze.
Kion tells everyone that they can wait until the fire ends in a day or so, but the idea of staying in darkness overnight frightens Tiifu too much, and the young lioness makes a desperate scramble to get out. Her furious clawing causes the mud and rocks to break away, sealing the group in. Kiara questions her friend on her behavior, where Tiifu reveals that she is afraid of the dark. After the princess scolds Bunga for frightening her more with his antics, the group decide that there must be a pathway that leads to Pride Rock somewhere. With three paths available, Kion assures Tiifu that they'll be there with her and chooses the middle one. Tiifu remains close to her friends with Kion leading the group, though her fear settles in when a strange cry appears in the distance.
Suddenly, from out of the ground, a golden mole grabs onto Kion's nose threateningly. Despite his demeanor, his claws tickle Kion's snout, causing him to sneeze and blow him away into Bunga's arms. He continues his fiery approach to the group until he learns that they're not interested in stealing his tunnels, and only wish to return home. He introduces himself as Kuchimba and offers to help them return home after his initial hostility. Zuri questions if he can get them home without eyes, but Kuchimba explains that he has ears and can smell and feel all the vibrations in the ground, which allow him to get around.
They start to follow Kuchimba, and Tiifu asks him if he ever gets scared of the dark. Kuchimba responds by telling her that there's nothin’ to fear down here, and how the noises and things she has been seeing are just her imagination. They reach a point where Kuchimba needs to return to his tunnels, much to Tiifu's disappointment. He tells them to take the main tunnel, and they thank the mole for his assistance, with Tiifu remembering his words.
After leaving, Kion swiftly returns, hoping that Kuchimba would still be there. He reveals to the group that there are three tunnels, with no indication as to which is the main one. Suddenly, they hear hoof steps, and Thurston appears from one of the tunnels, having wandered in. They deduce that the tunnel he came through must be the main one and enter, with Thurston following behind. When they reach the end, they discover three more tunnels. When asked if he knows which one he entered through, Thurston leaps through a tiny hole and gets stuck, prompting Kion to come up with another idea. He and Kiara start to track down Muhangus by scent, while Bunga frees Thurston.
Muhangus' scent becomes stronger on the other side of a wall, and Bunga begins to dig a whole. With Tiifu expressing her fears of Kion leaving, the leader responds that they'll be back soon, with the other cubs promising to be right by her side. Thurston states that he, too, will be by her side and pushes Kiara and Zuri out of the way to stand with her. On the other side of the tunnel, Muhangus is in a deep slumber. After being woken by Bunga he refuses to help until he has finished sleeping, but Bunga's antics persuade him to help.
After a long walk, they reach the exit. Tiifu darts off ahead, drawing criticism from Thurston. Bunga explains how she doesn't like being trapped in the dark, which causes the zebra to panic and runs, having not realized this before. His kicking leads to Muhangus warning him that the cave will collapse, and the commotion soon catches Tiifu's attention. She returns and calms Thurston and uses her newfound catchphrase, "there's nothing to fear down here". She offers to escort him out as his friend, and even ups the role to best friend when Thurston requests it.
When outside, Thurston leaves to tell his herd that he has a new best friend, while the others praise Tiifu for her bravery. Fuli, Ono, and Beshte arrive, having dealt with the fire and noticed their disappearance. Kion tells them that it's a long story, but Fuli notices Thurston as he enters another cave. When the zebra cries for help, Tiifu runs off to assist her new best friend.