Role in the film
Dr. Julius Plumford is first seen traveling on an elephant through the Indian jungle with his friend; Colonel Geoffrey Brydon, his daughter, Katherine "Kitty" Brydon, some British soldiers, and other Hindi people led by a jungle guide named Nathoo and his son, Mowgli.
At night, when Shere Khan; the mighty tiger, attacks two British soldiers, who broke the Jungle Law by hunting a few animals for fun and pleasure earlier, at the camp, Dr. Plumford and Colonel Brydon are alerted. Dr. Plumford asks the colonel what's going on and the colonel informs him that Sergeant Claibourne (one of the two soldiers who broke the Jungle Law) is in trouble, so Dr. Plumford sees to Claibourne immediately but is a little too late.
After Mowgli and his pet wolf cub, Grey Brother, are separated from everyone else due to the attack, Dr. Plumford checks on Nathoo (who received many wounds and scratches from Shere Khan when trying to defend an ungrateful, cowardly, and traitorous Indian named Buldeo, who also broke the Jungle Law and left Nathoo for dead) only to inform Colonel Brydon that he is sadly and unfortunately gone.
Years later, Dr. Plumford is seen guiding some English women, including an adult Kitty Brydon through the jungle to do some painting on some monkeys. When Dr. Plumford asks the women who can name the types of monkeys they see on the trees, he is disappointed to see that no one is answering, so he asks Kitty to do so. Once Kitty has named all the monkey types correctly, Dr. Plumford is delighted that "at least, he taught somebody something" only to be later teased by Kitty when she says she spotted "a spider monkey with a mustache wearing a white hat and linen suit."
A few moments later, after Mowgli (now a fully grown man raised by wolves) is captured by three mean British soldiers: Captain Boone, Lt. John Wilkins, and Sergeant Harley for "attempting to kill the Colonel's daughter and stealing a dagger from a maharaja," Kitty and Dr. Plumford try to convince Colonel Brydon that the jungle boy is actually Mowgli, since he was seen with a bracelet that once belonged to Kitty as a child and her mother before Kitty gave it to Mowgli, and to arrange a certain education to Mowgli about the ways of men again. First, Dr. Plumford suggests a nice hot bath for Mowgli, only to get himself splashed instead. Then, as Dr. Plumford shows a mirror to Mowgli while putting on a hat, Mowgli hits the mirror which in return hits the doctor back. Dr. Plumford is then seen with Kitty teaching Mowgli the alphabet, a few British customs, and some words through books and slideshows. Mowgli is given some lessons by Kitty even when being examined by Dr. Plumford; much to the doctor's annoyance. Dr. Plumford states that Mowgli "is picking up fast" when he notices him and Kitty getting closer together in the process.
Dr. Plumford is next seen inviting Mowgli to a dinner party while explaining that everything about the party is part of "all the bare necessities of life." After Colonel Brydon announces the engagement of his daughter to Captain Boone (as Boone proposed earlier and Kitty accepted), Mowgli asks Dr. Plumford what does this mean and the doctor regretfully replies that it means that Kitty and Boone are to wed and that Kitty belongs to him; much to both Mowgli and Dr. Plumford's dismay.
However, after Kitty breaks up her engagement with Boone due to he and his men's mistreatment of Mowgli, the next morning, Dr. Plumford goes with Colonel Brydon and Kitty to bring Kitty to the ship to England. Yet, on the road to Jaipur, they are ambushed by Indian bandits (who along with Boone, Wilkins, and their new recruit Sergeant Harley tried to capture Mowgli at first to lead them to the treasure they're after which failed due to Mowgli winning and Baloo the bear intervening) led by Buldeo and his friend Tabaqui. Colonel Brydon is the only one able to fight back and kill a few bandits with his gun only to get himself shot on the leg by another bandit.
Dr. Plumford tries to tend to Geoffrey, but Buldeo brutally removes him from the caravan and is about to kill him with a dagger but luckily, Mowgli arrives and pushes him aside. Then, Mowgli's wolf friends including Grey Brother and Bagheera the black panther join the attack and kill the rest of the bandits while the others flee for their lives. Then, Buldeo and Tabaqui flee with Kitty and her father taken as hostages.
Dr. Plumford asks Mowgli why they did this, and Mowgli replies because they want him to and know that he will come for Kitty. Dr. Plumford thanks Mowgli for saving his life, and Mowgli tells him that now he wants the doctor to save Baloo's life since Baloo was shot and wounded badly by Boone and his men when the bear was trying to protect Mowgli from being shot or captured by them.
In the final scene, after Boone's defeat, Dr. Plumford is seen proudly saluting Kitty and a triumphant Mowgli after having cured Baloo and the nearly left-to-die injured Colonel Brydon from their injuries. Dr. Plumford states that Baloo was "a very good patient" as he shows the bear his friends.