Based on the horror manga created by duo Fujiko Fujio, The Laughing Salesman tells the story of a salesman named Moguro Fukuzo, whose job is to help people fill gaps in their soul. However, in reality, he ruins people's lives if his clients backstab him or never ask him for help.
Moguri Irizou sneaks onto an expensive golf course to enjoy his game, since he can't afford membership fees. Moguro offers him a VIP membership, as long as he plays on certain days and plays alone. Irizou's boss finds out he's a member at the country club and pressures Irizou to take him. However while on the course, the two are apprehended and beaten up for playing with a fake membership card.
Warui Kanzou is a middle-aged man who is advised to stop exerting himself because of liver damage. Moguro offers Kanzuo an extract from a rare mushroom in Okuhida extract to restore his vitality, but warns him one bottle must last a month. After using it up too soon, Kanzou travels to Okuhida to find more, but after eating the wrong mushrooms, he turns into a mushroom himself.
Office worker Nagai Michinori has a four-hour commute to work. Moguro offers him a lavish condo that's extremely close to his office, but he's forbidden from using it during the weekend or on holidays. He gets drunk celebrating his good fortune with his boss and accidentally visits on a holiday, and soon after Nagai's co-workers find his corpse in his office locker.
Hideo Otaku is fascinated by the island of Tahiti, hoping to visit there somebody. Moguro shows him a VR nightclub that authentically recreates a visit to the island, but warns Hideo to only enjoy the club's pleasures inside its environment. Hideo falls in love with a beautiful server named Marie and invites her to a real beach resort, but is horrified when the sun and water reveal she's made of paint and melts.
The busy CEO of a Kindergarten business, Oyamano Taizou desires the freedom that children enjoy. Moguro enrols him to a kindergarten for adults, but warns that he must not bring in any external power imbalances. After being victimised by a bully in the kindergarten, Taizou later discovers that the man is head of a construction company seeking a building contract. Taizou agrees to the contract on the condition that the man allows Taizou to bully him in the kindergarten. For breaching the conditions, Moguro turns Taizou back into a child.
Moguro offers to protect the married celebrity Mizuno Shouhei who is photographed while dating a young idol from the same agency. He sends the elderly fixer Uma to deal with the photographer. However, Mizuno gets into trouble again and Moguro agrees to help only if he stops his philandering and cherishes his wife Taeko. Mizuno soon falls for Keiko, a woman in a bar and divorces Taeko to demonstrate his love. However, when he proposes to Keiko, she rejects him and reveals that she's the elder sister of a woman who committed suicide after Mizuno rejected her. Uma then presents Mizuno with many incriminating photographs to blackmail him.
Douki Manabu, one of a quartet of aging men who are drinking buddies since their school days is excited at Moguro's recommendation they invite a beautiful female classmate, Yoshiko, to attend one of their reunion parties. She swindles them all by pretending to have financial difficulties within her business, ruining the men's friendships and costing them their jobs. Moguro rekindles their friendship by turning them into a group of homeless drunks hanging out in ragged school uniforms.
Yokomichi Yukio is concerned about his son Manabu's academic ability, and Moguro sends in a tutor who teaches Manabu to play and have fun. Manabu's grades improve and Yukio agrees to him joining a mahjong game with his friends and Manabu wins. However Manabu is so successful, he then becomes a professional mahjong player.
Elderly Mukai Osamu leads a quiet life, but he is browbeaten by those around him such as his family and a fellow croquet player. Moguro advises him to be more assertive and when he changes his behaviour, people are surprised by his new attitude. However, he takes it too far and pushes over the croquet player who has been bullying him, exposing his baldness and false teeth. He also becomes too demanding with his daughter-in-law so Moguro commits him to living totally alone.
The lyricist Nikken, is not feeling well and Moguro introduces him to special drinks made from exotic ingredients, however he is not allowed drink anywhere else. The drinks not only improve his health, but improve his work output and he creates a successful drink campaign. However, after he drinks some of the product delivered to his home from the sponsor who used his work in the commercial, he turns into a root vegetable.
Moguro gives a scarf to office lady Norie who has had no luck with men, but he warns her to always wear the scarf when she is dating. After she wears the scarf she is proposed by two different men. Norie accepts a diamond necklace from the president of a business partner but takes off the scarf. When she returns to her apartment, the necklace gets caught in the elevator doors and she chokes to death.
Newlyweds Kaji Daisuke and his wife are both working full-time and although he wants to share the housework, he is completely useless at cooking and laundry. Moguro enrols Kaji in a housework culture school and he is completely changed, surprising his wife with his new skills and rekindling their romance. Kaji's wife is later appointed to a section chief position with a higher salary, so Kaji resigns his job so that he can focus on the housework. However, Kaji becomes so domestic, that Moguro sentences him to become pregnant with their baby.
