In a small town called Hemoville, lived a red blood cell named Ruby. Ruby had a very important job to do. She carried oxygen from the lungs to all the other parts of the body, which helped everyone in Hemoville stay healthy and strong.

One day, the Mayor of Hemoville announced there was a problem. Some cells were not getting enough oxygen because there was not enough of Ruby to go around. The Mayor decided to call on special helpers known as transfusions.

Ruby learned that a transfusion is when someone receives extra red blood cells from a donor—a generous person who gives some of their own cells to help others. A transfusion can make up for the shortage and allows every cell to get the oxygen they need.

Transfusions are not just for anyone. Doctors test to find a match. This is because everyone's blood has a type, like A, B, AB, or O. A match is important so the body can accept the new cells.

After a successful transfusion, the new red cells like Ruby work together to bring more oxygen to everyone. Hemoville is happy and the cells are healthier than ever, thanks to the kindness of donors and the smart matching by doctors.

Ruby was proud to have so many new friends helping out. She realized the importance of working together. And she also learned that being healthy depends not only on what's inside Hemoville but also on helping others.