The video shows a person's hands working on a car engine. The person is using a wrench to turn a bolt on a chain. The chain is attached to a gear, and the person is adjusting the tension of the chain by turning the bolt. The person's hands are dirty, indicating that they have been working on the engine for some time. The engine is black and appears to be well-maintained. The person's movements are deliberate and precise, suggesting that they are experienced in working on engines.