Είναι η Περίοδος Ταϊσό στην Ιαπωνία. Ο Τάντζιρο, ένα καλόκαρδο αγόρι που πουλά κάρβουνο, για να ζήσει, βρίσκει την οικογένειά του σφαγιασμένη από έναν δαίμονα. Σαν να μην έφτανε αυτό, η μικρότερη αδελφή του, η Νέζουκο, η μόνη επιζώσα, έχει μεταμορφωθεί σε δαίμονα. Αν και καταρρακωμένος από την νέα πραγματικότητα, ο Τάντζιρο αποφασίζει να γίνει Κυνηγός Δαιμόνων, ώστε να βρει τρόπο να κάνει την αδελφή του πάλι άνθρωπο, αλλά και να σκοτώσει τον δαίμονα που κατακρεούργησε τους δικούς του.

High school freshman Hiro Amanokawa activates a mysterious device left behind by his father called a "Digivice" that makes unknown creatures that cannot be seen by ordinary people, the Digimon, visible to his eyes. This is the story of this other side of the world that nobody is aware of. With their friends, Hiro and Gammamon dive into the mysterious world where these creatures live.

Twins Kazuya and Tatsuya, and their neighbor Minami have played together since they were children and built an unbreakable bond. But with puberty, the twins realized something: Minami is a girl, and three is a crowd.

As the trio tries to preserve their relationship, Kazuya's pledge to make Minami's dream come true by taking her to Koshien with his baseball pitching skills makes the slackerish Tatsuya wonder about himself, and his own goals. But Minami has another dream she wants fulfilled, and as the twins continue to push themselves, with Minami in the middle, a life-changing tragedy leads one twin down a path he once never would've considered...

In a distant future, Tetsuro is a human boy who wants his body replaced with a robotic one. This is possible, but to do so he has to reach the Immortal Planet onboard the space train Galaxy Express 999. Maetel, a beautiful and mysterious blonde woman dressed in Russian style, joins him in the long journey through space. Every episode sees our heroes arriving in a new planet's space train station.