Part 3: Beat Lenora — Nacrene City Gym, badge 2

Beat Lenora — Nacrene City Gym, badge 2 opens 2 areas.

Where to go

1. Pinwheel Forest

   Wild: Basculin 100% · Lv 5-20, Audino 95% · Lv 12-15, Goldeen 60% · Lv 35-55, Tympole 40% · Lv 12-15 +18 more

2. Castelia City

   Wild: Zorua Lv 10

Everything you can have caught by this checkpoint · Open the interactive guide

It also doesn't say when 4 of its areas open up, so they are listed together in the last part rather than guessed into the story.