One evening in Amato's garage, he shows Pian his sketch for their science project, which MechaBot compares to chicken scratches. Meanwhile, a robot melts a hole through the preschool's wall and steals art to hang in frames in his warehouse, later conspiring to steal an artist as well. That morning, the children cry over their missing artwork and Amato aboard his Mechabike happens to pass them, and the teacher explains what happened. Amato encourages a kid to draw a new one, and he asks if he can teach him. MechaBot says he ought to take lessons from a chicken instead, and shows him Amato's project sketch. Several kids starting crying again from how bad it is.
The robot thief enters the class at the roof window and descends. Rubika identifies him to be Paintasso, who steals valuable art. The teacher huddles the kids behind a table as Amato and MechaBot fend off Paintasso, who shoots acidic paint. He jumps to the other side of the room to avoid a Mechablaster attack and flies off with a child. Another kid offers Amato a hobby horse to mechanize with, and he flies towards Paintasso aboard his MechaHorse. MechaBot headbutts Paintasso off his aircraft, but he launches a rocket blast at the him and Amato. Mechamato forms in time to embrace the kid before crash-landing into a warehouse.
Paintasso reappears to attack, but Amato's sketch catches his eye. The hero punches Paintasso out the door for touching his drawing, but he disappears along with it. At class, Mr. Jamie doesn't believe that the sketch was stolen, and tells Amato and Pian that if they don't have it by tomorrow, they super-flunk. Mara accompanies them in finding Paintasso's base, which she deduces to be an abandoned graffiti-ridden warehouse. Mechamato attempts to sneak past the security cameras inside, but MechaBot impulsively rushes up the stairs, triggering a paint bomb.
Enraged at MechaBot for insulting the "masterpiece" behind him, Paintasso sets off more bombs, blasting Mechamato outside. He mechanizes with some old bicycle wheel rims to roller skate towards Paintasso and slice his paint gun with a kick. Paintasso jumps in the air, pushes buttons on a palette-like machine, and activates his upgraded form. Mechamato attempts to evade his paint missiles, but gets tripped up. Paintasso then takes Mara and Pian under each arm, saying he'll only give them up if Amato surrenders himself to make more art for him.
As MechaBot talks to Paintasso, Mara gestures Amato to some scrap material to mechanize with to defeat Paintasso. In his fortified "Paintbuster Mode", Mechamato is unaffected by the paint missiles as he runs towards Paintasso. Pian helps Mara onto her wheelchair once Paintasso lets go of them. Mechamato strikes him out of his upgraded form, and his final attack is to spray him with paint. He explains that Paintasso no longer has to steal art now that he's a walking masterpiece. It works, and Paintasso thanks Amato, since he only has to look upon a mirror to see art. Amato then captures him in the Mechanizer along with the mirror. The colorful battle ground becomes a tourist attraction.
This episode provides examples of:
- Awesomeness by Analysis: Amato and Pian are very impressed when Mara deduces that Paintasso's hideout is an abandoned grafitti-ridden warehouse since he'd like to store his stolen artwork at such a place. Moreover, she turns out to be right.
- Dramatic Spotlight: When Paintasso is gleeful to become a walking masterpiece, a spotlight can be seen shining down on him at one point.
- Hand Signals: When Mara and Pian are held hostage under Paintasso's arms, MechaBot converses with the latter to distract him while Mara gestures to Amato her idea to defeat Paintasso. Pian comically misses the point and plays around with hand signals of his own.
- Heist Episode: Downplayed. In episode 7, to take back his drawing, Mechamato sneaks into the abandoned warehouse where Paintasso also stores the stolen preschoolers' art. As they manuever past security cameras with laser pointers, MechaBot questions why he and Amato are the ones sneaking in like a bunch of thieves.
- Immediate Self-Contradiction: One child at the preschool warns another student not to talk to strangers when Paintasso appears at their ceiling, right before the kid asks for the intruder robot's name and where he lives.
- Running Gag: Amato's sketch makes kids cry upon looking at it out of how ugly it is. This happens thrice; firstly in the preschool, secondly just after rescuing a kid from falling, and thirdly right at the end, where the same kid sees Amato's sketch framed on an upstairs floor and faints.
- Smoke Bomb: Paintasso conceals his escape by throwing paint bombs at Mechamato, resulting in colorful smoke that stops the hero from seeing him.
- True Art Is Incomprehensible: In-universe. Paintasso steals preschoolers' drawings, considering them masterpieces, but when he steals Amato's drawing, that even the preschoolers consider ugly, he hangs it up in a golden frame and thinks it's genius, despite having no idea what it means.Paintasso: [to MechaBot] Hideous? You know absolutely nothing about art, monsieur!
- Would Hurt a Child: Paintasso states that besides stealing paintings, he is also a kidnapper. Then he shoots acid-like paint in a class of preschoolers and flies away with one of them.
