Mowgli has been abducted by the Bandar-log, or Monkey People. This was perhaps an inevitable consequence of his visiting these widely loathed creatures, shunned and avoided by all the other animals of the jungle. When they first whisk him off to the Cold Lairs, an abandoned human city, the monkeys are fascinated with this man-child and proceed to treat him like a bright, shiny toy. But as with all toys, the novelty soon wears off, and the monkeys get bored with Mowgli. Unfortunately, that still doesn't mean that they're prepared to let him go, so he must be rescued by his friends.
Initially, one of those friends is Baloo the bear, despite the fact that he and Mowgli have recently had a bit of a falling out. Apparently, Mowgli hadn't been paying attention to Baloo's lessons about the Law of the Jungle, and so the big bear whacked him over the head, causing Mowgli to run off in a huff.
Despite this pleasant incident, the two remain firm friends, and Baloo is only too happy to accompany Kaa and Bagheera on their daring rescue mission. The problem, though, is that the rather plump Baloo is unable to keep up with his companions. Kaa and Bagheera need to move quickly throughout the jungle, making half a night's journey at full speed. But Baloo simply isn't fit enough to make such a journey, and after stopping to catch his breath, he reluctantly decides that Kaa and Bagheera should go on ahead without him.