The video shows a swimmer swimming in a pool. The swimmer is wearing a blue swimsuit and a swim cap. The swimmer is performing the butterfly stroke, which is a swimming style where both arms move simultaneously underwater and both legs move simultaneously above water. The swimmer is moving forward in the water, and the camera follows the swimmer's movements. The pool has multiple lanes marked by floating lane dividers. The water in the pool is clear and blue. The video is taken from an underwater perspective, and the swimmer is the only person visible in the video.