Get ready for a delightful adventure as My Melody & Kuromi brings the beloved Sanrio characters to life in a charming stop-motion animation series. Celebrating the 50th anniversary of My Melody and the 20th anniversary of Kuromi, the series takes viewers on an adventure in Mariland, their whimsical home.

Ever since the death of his father, the burden of supporting the family has fallen upon Tanjirou Kamado's shoulders. Though living impoverished on a remote mountain, the Kamado family are able to enjoy a relatively peaceful and happy life. One day, Tanjirou decides to go down to the local village to make a little money selling charcoal. On his way back, night falls, forcing Tanjirou to take shelter in the house of a strange man, who warns him of the existence of flesh-eating demons that lurk in the woods at night. When he finally arrives back home the next day, he is met with a horrifying sight—his whole family has been slaughtered. Worse still, the sole survivor is his sister Nezuko, who has been turned into a bloodthirsty demon. Consumed by rage and hatred, Tanjirou swears to avenge his family and stay by his only remaining sibling. Alongside the mysterious group calling themselves the Demon Slayer Corps, Tanjirou will do whatever it takes to slay the demons and protect the remnants of his beloved sister's humanity.

Denji is robbed of a normal teenage life, left with nothing but his deadbeat father's overwhelming debt. His only companion is his pet, the chainsaw devil Pochita, with whom he slays devils for money that inevitably ends up in the yakuza's pockets. All Denji can do is dream of a good, simple life: one with delicious food and a beautiful girlfriend by his side. But an act of greedy betrayal by the yakuza leads to Denji's brutal, untimely death, crushing all hope of him ever achieving happiness. Remarkably, an old contract allows Pochita to merge with the deceased Denji and bestow devil powers on him, changing him into a hybrid able to transform his body parts into chainsaws. Because Denji's new abilities pose a significant risk to society, the Public Safety Bureau's elite devil hunter Makima takes him in, letting him live as long as he obeys her command. Guided by the promise of a content life alongside an attractive woman, Denji devotes everything and fights with all his might to make his naive dreams a reality.

Togashi is born to run. As a kid, he is naturally gifted and wins every 100-meter race without effort. But in sixth grade, he meets Komiya, a transfer student who is full of determination but lacks technique. In teaching him, Togashi gives Komiya a new purpose: to win no matter what. Years pass by, Togashi and Komiya meet again as rivals on the track and reveal their true selves.