Olga collects flowers near her house. Suddenly, Krash and Chiko tell her the terrible news: her back is white-colored. This scares Olga and makes her examines her back. Krash and Chiko laugh and explain that they pranked her because today is the April Fools Day.
Later, during a tea party with Carlin, Olga tells him about this case. Carlin agrees that it's not funny and takes a big sip of tea. Suddenly, he starts coughing and loses consciousness. Olga runs home in horror to get a first-aid kit. When she returns, she learns that Carlin is fine, telling her that this is how one makes a funny prank. Olga faints. Carlin brings her to her senses and asks her not to take everything so seriously. Olga offers her own version of a harmless prank and shows him a joke with a purse on a rope.
Wally composes a verse when a purse falls near him and knocks over an inkwell. He sees the rope and finds Olga in the bushes. Olga explains her joke to him and realising Wally is a person that doesn't understand jokes, leaves. Meanwhile, Dokko prepares for a trip on the balloon. When Olga throws a purse in front of him, Dokko notices the rope, takes it for himself, and throws the purse away. Olga starts looking for a new rope and decides to take the one that ties the balloon. Picking it up, she accidentally dirties her back with the balloon basket's white paint, unwinds the rope and unties the balloon. It takes off and knocks Wally off a cliff, while the basket destroys Dokko's house. He notices that Olga's back is full of white paint, but she thinks he's trying to prank her and praises him for a good joke. In the evening, when Olga returns home, she hears cries for help from Wally, who is stuck on a tree with a balloon. Olga takes it as a joke and continues walking.
Tropes:
- April Fools' Plot: As the episode's name indicates, it's set on April 1st, with Krash, Chiko and Carlin pulling pranks on Olga, who later decides to do her own, "harmless" jokes. On the other hand, Wally and Dokko are too busy with their usual jobs to make any pranks.
- Cash Lure: Olga's prank is for someone to see a wallet lying around, trying to take it, and failing as she pulls it away with the string.
- Dude, Not Funny!: Olga thinks her friends' April Fools jokes are not funny but rather mean... at first.
- Prank Gone Too Far: Carlin's prank drove Olga to faint, while her own prank led to the destruction of Dokko's house and Wally being stuck on a tree.
- Shout-Out: Olga's prank with the purse is based on the one done by Shapoklyak in Cheburashka.
