Vermilion Gym

The Vermilion Gym is the third gym of the Kanto region, located in Vermilion City and its champion is Lt. Surge. Upon defeating him, you will recieve the Thunder Badge, which enables Pokémon to use Fly outside of battle. You will also unlock the option to purchase TM 24 - Thunderbolt.

In order for the player to access the gym, a Pokèmon needs to know Cut, which is gained by helping the Captain on S.S. Anne.

Lt. Surge's room is blocked by an electrical barricade. You can turn the barricade off by disabling two switches in an order. The position of these switches is random for every player.