Red Blood Cells AA2153 and AC1677 are getting accustomed to their jobs and even have enough energy to joke around during their downtime. They head to the kidneys to wash away the dirt accumulated on the job, where they meet the Glomeruli who work silently to filter the blood. A young Glomerulus warns Red Blood Cell to be careful when getting close to the ureter. When the Red Blood Cells arrive at the efferent arteriole, they hear the ominous sound of something blocking the nearby ureter…