In Virbank City, you'll encounter Roxie, the Gym Leader, who is also the bassist of a punk rock band. She'll be performing at the Virbank Gym. Before you can challenge her, you'll be introduced to Pokestar Studios, a new feature in Black 2 and White 2. A man named Brycen, a former Gym Leader and movie star, will invite you to participate in a movie. This is an optional but fun side activity that can earn you rewards and unlock new movie scenarios.
To progress the main story, you need to head to the Virbank Gym. However, before you can challenge Roxie, you'll need to help her band. After a brief interaction, she'll head into the Gym. Make sure your team is healed and ready. The Pokémon Center is conveniently located near the Gym. Consider catching a Magnemite from the Virbank Complex if you haven't already, as its Steel typing provides resistance to Poison-type moves, and its Electric-type attacks are super effective against Flying-types, which Roxie might use.