Sailor Moon's Adventures of the Jungle Book is the fourth adventure in the Sailor Moon's Adventures series, and the debut of Sailor Venus - Mina Aino back into the team.
Ursula the Sea Witch disguises herself as Vanessa in order to lure the Senshi out into the open, where they are attacked by her partner, Jafar. The villains injure Tuxedo Mask when he tries to save the girls, but they are foiled by the appearance of Sailor Venus, who, in this incarnation, is a researcher from London living in a residence by the Man Village.
Mowgli, a young orphan boy, is found in a basket in the deep jungles of Madhya Pradesh, India. Bagheera, a black panther and Usagiwho discovers the babyalong with Usagi and the others, promptly takes him to a mother Indian Wolf who has just had cubs. She raises him along with her own cubs and Mowgli soon becomes well acquainted with jungle life. Mowgli is shown ten years later, playing with his wolf siblings.
One night, when the wolf tribe learns that Shere Khan, a man-eating Bengal tiger, has returned to the jungle, they realize that Mowgli must be taken to the "Man-Village" for his own safety. Bagheera and the others volunteers to escort him back.
They leave that very night, but Mowgli is determined to stay in the jungle. He, Bagheera and the others rest in a tree for the night, when Kaa, a hungry Indian Python, appears and hypnotizes Mowgli into a deep and peaceful sleep, traps him tightly in his coils and tries to devour him, but fails when Bagheera and the others intervenes. The next morning, Mowgli and Rini tries to join the elephant patrol led by Colonel Hathi and his wife Winifred. Bagheera finds them and they argue which results in Bagheera and the others leaving Mowgli on his own. Mowgli soon meets up with the laid-back, fun-loving sloth bear Baloo, who shows Mowgli the fun of having a care-free life and promises to raise Mowgli himself and never take him back to the Man-Village.
Mowgli now wants to stay in the jungle more than ever. Shortly afterwards, Baloo is tricked and outsmarted by a gang of monkeys who kidnap Mowgli and take him to their leader, King Louie the orangutan, who makes a deal with Mowgli that if he tells him the secret of making fire like a human, then he will make it so he can stay in the jungle. However, since he was not raised by humans, Mowgli does not know how to make fire. Bagheera and Baloo, along with the others arrive to rescue Mowgli and in the ensuing chaos, King Louie's palace is demolished to rubble. During the confusion, Serena manages to spot some rather strange crystals hidden in a crumbling pillar, and snatches them before the palace falls apart completely.
Bagheera, now in possession of the crystals given to him by Serena, speaks to Baloo that night and convinces him that the jungle will never be safe for Mowgli so long as Shere Khan is there. In the morning, Baloo reluctantly explains to Mowgli that the Man-Village is best for the boy, but Mowgli accuses him of breaking his promise and runs away. As Baloo sets off on foot in search of Mowgli, Bagheera rallies the help of Hathi and his patrol to make a search party. However, Shere Khan himself, who was eavesdropping on Bagheera, Sailor Scouts and Hathi's conversation, is now determined to hunt and kill Mowgli himself. Meanwhile, Mowgli has encountered Kaa once again in a different tree and the hungry python exacts his revenge by hypnotizing Mowgli again, and tries to eat him, but thanks to the unwitting intervention of the suspicious Shere Khan, Mowgli awakens again, tricks the snake again, and escapes.
As a storm gathers, a depressed Mowgli encounters a group of puckish but friendly vultures who closely resemble English rock band The Beatles, and they agree to be his friends as they too are outcasts, and feel that everyone has to have friends. Shere Khan appears shortly after, scaring off the Vultures and confronting Mowgli. Baloo and the others rush to the rescue and try to keep Shere Khan away from Mowgli, but Baloo gets injured. The tiger is about to kill his rival when he is hit by a powerful attack from a mysterious Sailor Senshi. Taking advantage of the distraction, the vultures drag Baloo's unconscious body out of the crossfire. When lightning strikes a nearby tree and sets it ablaze, the vultures swoop in to distract Shere Khan while Mowgli gathers flaming branches and ties them to Shere Khan's tail. As fire is his only fear, the tiger panics and runs off.
But no sooner does the tiger flee when the Senshi are suddenly trapped in a black bubble by Jafar, who, alongside Ursula, threaten Mowgli and Bagheera to hand over the crystals, which are revealed to be shards of the legendary Crystal of Nightmares, or else the girls will die. Mowgli, not wanting his new friends to perish, snatches the crystals away from Bagheera and is about to hand them over, but the mysterious Senshi appears again and attacks Jafar, disrupting his control of the bubble. The freed Senshi recognize their savior as Sailor Venus. She is also accompanied by her white cat, Artemis. As the Sea Witch and Grand Vizier prepare to battle the heroes, they are called away by Maleficent for an unknown reason, and reluctantly teleport out of there without the Crystals in hand.
Bagheera and the team take Mowgli to the edge of the Man-Village, but Mowgli is still hesitant to go there. His mind soon changes when he is smitten by a beautiful young girl from the village who is coming down by the riverside to fetch water. After noticing Mowgli, she "accidentally" drops her water pot, and Mowgli retrieves it for her and follows her into the man village. But as the two children leave, Luna spots the retreating figure of Sailor Venus enter the village from a secret corridor and change back into Mina Aino without anyone noticing as far as she can tell.
After Mowgli chooses to stay in the Man-Village, Baloo and Bagheera decide to head home, content that Mowgli is safe and happy with his own kind. The next day, the Sailor Scouts in civilian mode confront Mina at her home about her actions yesterday, to which she reveals she already had her memories restored before the others did thanks to Artemis, and that she needed to save the girls as they were her friends in the past. Though they are a bit disappointed that Mina didn't arrive earlier on their quest, the other girls agree to let her join the team once more, with Rini, who remained on the ship for the whole adventure, being the happiest of the group.