The phrase "in high gear" means that something is moving or operating at a very fast pace, with great energy and activity. It can be used to describe a situation where things are happening quickly and efficiently, or when someone is working hard towards achieving their goals. The term comes from the world of mechanical engineering, specifically referring to the highest level of gearing in a transmission system that allows for maximum speed and power output. In everyday language, it's often used figuratively to describe situations where things are moving at an intense pace or when someone is working very hard towards achieving something.