While traveling through the snowy forest at night, the Lion Guard comes across a big frozen lake. Anga spots the last moja kwa moja stone on the other side, causing Ono to note that they are almost at the Tree of Life, much to Kion's relief. Kion asks Anga how long it will take to get around the lake, who reports it might take them all night since it's big. Feeling pain in his scar, Kion irritably insists that they get going. At that point, Bunga calls Kion to show him how the lake is hard, causing Ono to explain how the lake has frozen over due to the extreme cold, turning the water into ice.
Seeing the water is hard enough to walk on it, Bunga suggests crossing the lake. While some are unsure about the ice, Kion agrees with Bunga, believing the lake is the fastest way to go. The Guard begins crossing the lake, with some stumbling on the slippery surface. Unfortunately, the combined weight of the Lion Guard begins cracking the ice, sending them all running as the lake begins to fragment. While the Lion Guard makes it to land, Makini gets stuck on a small piece of ice. With Anga unwilling to risk toppling Makini's island with wind from her wings, Kion and Fuli attempt to rescue Makini.
While trying to reach another slab of ice, Makini accidentally falls into the icy water. Kion and Fuli soon reach her and pull her out, taking her away from the ice. Back on land, Kion asks Makini for Tuliza for his scar. Unfortunately, Makini realizes she lost her staff and their stash of Tuliza at the lake, with Anga confirming it has sunk. Kion reassures Makini, pointing they are at least close to the last moja kwa moja stone. When Anga points them to it, Ono despairs upon realizing that they can't activate the painting without Makini's staff, leaving them unable confirm if it's really a moja kwa moja stone.
Kion then asks Ono to remember Rafiki's map, saying the Tree of Life must be close by if this is the last moja kwa moja stone. Ono recalls the map, remembering that there is a narrow mountain pass up ahead, with the Tree of Life on the other side. When Anga spots the pass, Kion tells the others to head for it. Fuli tries to stop Kion, believing they should wait until morning when they can see better. Kion turns her down, saying he isn't going to get better just waiting around, leading Ono to assure Fuli that Kion will get better at the Tree of Life, with Fuli hoping he does before telling the others to move.
As the Guard makes its way to the pass, a grey owl named Ullu sees them coming and, believing the Guard to be a threat, heads into the pass to warn the "Night Pride". As the Guard reaches the pass, Bunga spots a beehive above the entrance and makes his way towards it, planning on eating the bees and the honey. Ignoring Kion's warnings, Bunga tries to reach for the beehive, dislodging the rocks below him and accidentally causing a rock slide that blocks the entrance to the pass. Enraged, Kion turns to the frightened Guard, angrily asking Bunga why he didn't listen to him before realizing he isn't there.
It is then revealed that Bunga got stuck between the rocks, much to Kion's frustration. Though Makini tries to calm him, Kion snaps at her, pointing how their only entrance to the Tree of Life has been blocked. Kion orders the Guard to start clearing the rocks and set Bunga free. Meanwhile, Ullu is shown to have brought the Night Pride to the pass, revealing them to be a group of brown-furred lions with a marking on their shoulder. Coming across the newly formed rock slide, their leader, a young lioness named Rani, thanks Ullu for warning them, saying they can take it over from here as the owl leaves.
Rani hears some of the Guard's voices and, not recognizing them, asks her uncle Surak for advice. He confirms them as strangers, remarking they must be powerful to have caused a rock slide. Fearing they might be dangerous, Rani turns to Nirmala, who suggests a calm approach, thinking the strangers might be peaceful. Still, Baliyo, Rani's younger brother, becomes suspicious and starts climbing the slide, wanting to take a look. He reaches the other side and, seeing the Guard below, listens to Kion say how, as soon as they clear the rocks, nothing will stop them from getting to the Tree of Life.
Misreading the situation, Baliyo reports the strangers as mean before setting off to stop them, ignoring Rani's warnings. Frustrated, Rani leads the others to help him, chanting "With strength and respect, Night Pride protect". Baliyo takes the Guard by surprise, ambushing Kion while Anga informs Fuli of other lions coming. Taking charge, Fuli has Beshte and Anga help her fight while Makini and Ono try to free Bunga. At one point, Fuli tries to reason with Rani, though the lioness refuses to listen, blaming them for the rock slide and for Kion attacking Baliyo, even though it was her brother's fault.
After fighting for a while, Kion loses his temper and uses the Roar of the Elders on Baliyo, sending him flying. The Roar shocks the Night Pride, with Surak mentioning on having heard stories about it as a young cub. Surak asks Rani on how to proceed, only for her to rush past him in a mad frenzy. At this point, Fuli gets Kion to calm down just in time for him to be tackled by Rani. Holding Kion down, Rani presents herself as the leader of the Night Pride, a group of lions dedicated to protecting animals at the Tree of Life from those who would harm them, making it clear that she sees Kion as a threat.
Remorseful, Kion tries to apologize and explain himself, though Rani refuses to listen. Fuli convinces Rani to let him go, saying they don't want to hurt anyone. Kion presents himself to Rani, explaining how he and his friends have travelled all the way to the Tree of Life to get help. Rani, though, treats Kion coldly, reminding him he sent her brother flying with his Roar, and thus she can only imagine the damage he could to everyone at the Tree of Life. Ignoring his protests, Rani furiously tells the Lion Guard they will never be welcomed at the Tree of Life and to leave and never return before departing.
The Lion Guard is left shocked and dismayed at this surprising turn of events, Kion especially. When Anga asks what happens now, Bunga reminds them he is still stuck, prompting them to try and free him. Bunga tries consoling Kion, saying he doesn't have to listen to Rani because he has the Roar and he can use it to fight her. Fuli and Beshte oppose this, wanting to be welcomed at the Tree of Life instead of forcing their way in. Beshte in particular has no ill will towards the Night Pride, believing they were just defending their home, something the Lion Guard would have done in the same place.
When Makini wonders if this they are not going to the Tree of Life, Fuli assures her they just need to come up with another plan. When Fuli turns to Kion for help, the Guard finds him walking away despodently. Knowing Kion needs some time alone, the Guard goes back to helping Bunga. On the other side of the pass, the Night Pride is seen approaching the Tree of Life, where they come across Baliyo, a little rattled but otherwise okay. When Baliyo asks about the strangers, Rani insists that it doesn't matter because they are gone, though she figures she should tell Queen Janna what happened.
Leaving Baliyo with Surak and Nirmala, Rani enters the Tree of Life and makes her way to a chamber deep inside the tree. She approaches the Queen, also revealed to be her grandmother. Rani wakes Janna up and informs her of the strangers that blocked the mountain pass, saying they were being led by a scarred lion, before eventually fighting and banishing them. Rani then makes a passive remark to Janna over how the leader had a powerful roar that sent Baliyo flying. Hearing this, Janna's face suddenly turns serious as she muses to herself that the Roar "has finally returned".
In the meantime, Kion is seen walking alone in the snow, eventually making his way to the lake of ice and the last moja kwa moja stone, as he reckons with his feelings of guilt and self-pity over his failure. However, noticing the rest of the Guard try to free Bunga, Kion comes to see that there is more to the journey than just him. Realizing things will be fine so long as he has his friends with him, Kion starts making his way back to the pass, by which point the others have managed to free Bunga from the rocks. On his return, Kion admits to the Guard that he lost control of the Roar again.
Believing Rani was right to banish him, Kion apologizes to everyone, noting they've all followed him loyally only for him to ruin everything in the end. The others forgive Kion, knowing he didn't mean to lose control, and suggest talking to the Night Pride again to explain themselves. Ono also assures Kion that, even without Tree of Life, they can still find another way to heal Kion's scar. Regaining his confidence, Kion refuses to give up, pointing how Ono's eyes also need to be healed. Meanwhile, Janna has told Rani about the Elders to Rani, who seems unsure about how it can be a good point.
Reluctant to allow Kion into the Tree of Life, Rani tries to argue by mentioning Kion's scar, only for Janna to explain how they all have their scars, quoting "Sisi ni sawa" at her. Though Rani is still confused, Janna says all will be clear soon enough, for now telling her to bring Kion and the others to the Tree of Life. Obeying Janna, Rani leaves to join the rest of the Night Pride outside, finding Baliyo eager to go back to the pass and force the strangers to leave. Rani, however, explains Janna was actually excited about the roar, and has asked that the strangers be welcomed at the Tree of Life.
While Surak and Nirmala agree to the plan, Baliyo protests by arguing that the roar sent him flying, leading Nirmala to calm him. Wanting to be alone, Rani leaves the Night Pride and, some distance away, calls for her deceased parents, Sãhasí and Ãnanda, who appear in the clouds shortly. Rani asks them for advice, not fully agreeing with Janna's plan to allow the Lion Guard into the Tree of Life, worried they might cause trouble. Her parents advise her to trust in Janna, saying she is wise and knows what she's doing. They also encourage her to listen to Janna, noting Rani will be Queen one day too.
Seeing they are right, Rani thanks her parents for their help. The Night Pride are then seen making their way through the canyon, hoping to catch the strangers before they've gone too far. However, they soon find them at the entrance, having cleared the rock slide but not moved closer to the Tree of Life. Surprised, Rani approaches Kion, who apologizes for using the Roar. Kion tells Rani that even if she won't allow him to enter the Tree of Life, he begs her to take Ono instead, noting he wasn't part of the earlier fight and his eyes need to heal, clearly not wanting him to pay for his friend's mistakes.
Touched by Kion's selfless devotion to his friends, Rani declares they are all welcome at the Tree of Life, much to Kion's relief. Bunga then presents the group as the Lion Guard, though Baliyo notes they only have one lion. Now on better terms with each other, Rani starts leading the way to the Tree of Life. Along the way, Baliyo asks Kion to never roar at him again, with Kion promsing he won't. Both groups reach the end of the canyon as the sun begins to rise. As the Lion Guard stops to marvel at the beautiful sight and the end of their journey, Rani welcomes them all to the Tree of Life.