In the video, a person is seen working on a car's brake system. The person is using a wrench to loosen the brake caliper, which is a crucial part of the brake system. The brake caliper is attached to the brake rotor, which is the part of the wheel that makes contact with the brake pads to slow down or stop the vehicle. The person is likely performing maintenance or repair work on the brake system, such as replacing brake pads or fixing a malfunction. The video provides a close-up view of the brake caliper and rotor, allowing the viewer to see the details of the components and the actions being performed.