This video shows a close-up of a blood vessel with a green cell floating in the bloodstream. The cell is moving towards a white cell, which is positioned on the vessel wall. The white cell appears to be a macrophage, a type of immune cell that is responsible for phagocytosis, or the process of engulfing and destroying foreign substances. The green cell is likely a pathogen, such as a virus or bacterium, which the macrophage is attempting to eliminate. The video provides a detailed look at the interaction between the two cells and the process of phagocytosis.