The main protagonist is Akira, a 12-year-old boy with a Rockruff. Joining Akira is Mana, a 8-year-old girl who owns a Rowlett and Tokio, a 16-year-old boy who owns a Type: Null with something mysterious. The plot centers around Akira who is on vacation in Alola. During his vacation, he stumbles upon a lonely Rockruff and befriends it.
Pokémon Horizon contains examples of:
- Adorably Precocious Child: Mana is an 8 year old who can battle with Pokemon.
- Something Completely Different: The Island challenge is open to anyone of all ages.
- Expy: All of the characters are expys of the characters of Sun and Moon:
- Akira is Elio and Hau
- Mana is Selene
- Tokio is Lillie and Gladion
- Duilio is Guzma
- Napo is Plumeria
- Mejiya is Lusamine
- Little Miss Badass: Mana
- Out of Focus: All Pokémon not from Gen VII (except for their Alolan forms) are absent entirely.