Thonky.com's Pokémon Legends: Z-A Walkthrough

Cate asks you to join her gathering where they will await the Starmie that descend from the sky.

How to Start the Mission

This mission becomes available after you talk to Mable during Main Mission 35: Reaching Rank A. Talk to Cate, who is northeast of Magenta Plaza Pokémon Center (which is in the northwest part of the city) to start the mission.

How to Complete the Mission

You can catch Staryu in Wild Zone 2 at night, then use a Water Stone on Staryu to turn it into Starmie. You can purchase a Water Stone at the Stone Emporium, whic is in the southern part of the city, south of Vernal Pokémon Center. If it's not night time, you can use a bench to turn it into night time (there is a bench outside of every Pokémon Center, for example).

Put the Starmie into your party, then at night, go back and talk to Cate.

Mission Rewards

You get 2800 Pokédollars, 1x Eviolite, and 1x Big Pearl.