The storyline of Pokémon Legends: Arceus takes place in the ancient Sinnoh region, called Hisui, where you are a new recruit for the Galaxy Team, a group that studies Pokémon. Your main goal is to complete the region's first Pokédex by catching and researching Pokémon. The story is driven by a space-time rift that causes Noble Pokémon to become frenzied, a problem you must solve to understand and calm the rift.  

• An ancient world: The game is set in the distant past, before the modern Sinnoh region and its Pokémon League existed. You arrive in Hisui after a mysterious voice, revealed to be Arceus, sends you there through a space-time rift. 

• Join the Galaxy Team: You are found by Professor Laventon and brought to Jubilife Village, where you join the Galaxy Team's Survey Corps. Your primary mission is to explore Hisui and fill out the region's first Pokédex. 

• Noble Pokémon and the rift: The space-time rift causes "Noble Pokémon" to become berserk, and you must find a way to calm them. You will interact with the Diamond and Pearl clans, who have different beliefs about these legendary Pokémon. 

• Conflict with the team: After defeating the Noble Pokémon, Commander Kamado blames you for the rift and banishes you from the village. This forces you to continue your research alone to find the true cause and end the disturbance.