In Pokemon Black and White, the fifth gym is the Driftveil City Gym. The Gym Leader is Clay, and he is a specialist of Ground-type Pokemon.
Before you can challenge the gym, you’ll need to go to the Cold Storage to find Team Plasma. Yep, that’s still a different story. When you defeat Team Plasma in the Cold Storage, head back to the gym.
When you enter the gym, talk to Clyde to receive a Fresh Water. In the middle of the room will be this platform with two arrows, a green one on the right and a purple on on the left). The green arrow takes you down and the purple takes you up. Step on the platform in the middle of the room and press the green arrow. You will then be taken to the actual gym.
After arriving, head to your right and you’ll be challenged by Worker Felix. Continue going right and you’ll see another green arrow. Press it. After you go down one level, go up to the very back of the gym and head to the left. Continue following the path and you’ll be challenged by Worker Sterling. Defeat him, get on the platform next to him, and press the green arrow.
After you go down yet another level, there will be two platforms, one on the right and one to the north of the platform you’re on. Step on the platform on the right and press the purple arrow. Go right and you’ll be challenged by Clerk M Issac. Continue going right and there will be two platforms, the one you are on and the one above it. Take the one above it to be challenged by Worker Don.
Go back down and go back to the platform with Clerk M Issac next to it. Press the green arrow and go left after going down a level. Go to the very back platform and press the purple arrow. You’ll then go up two levels.
You’ll see this platform with a box type thing around it next to the platform you are on. Go up onto the path and go right to be challenged by Clerk F Katie. Defeat her, get onto the platform next to her and press the green arrow to be taken to the Gym Leader’s room where Clay will be waiting.
Clay has a lv29 Krokorok, a lv29 Palpitoad, and a lv31 Excadrill.
Fighting, Grass, and Water-types will make this gym very easy. His Krokorok’s moveset is Swagger, Torment, Bulldoze, and Crunch. Palpitoad has Muddy Water and Aqua Ring. His Excadrill has Hone Claws and Rock Slide. When you defeat him, you’ll receive the Quake Badge and TM78 which is Bulldoze. You won’t receive the TM until you meet him at the Chargestone Cave entrance.