Episode 13

Plot
Following the hemorrhagic shock, U-1146 tries to find survivors; he finds no red blood cells, but instead a normal cell who tells him that the blood cells were sucked up by the wound, and that there is no oxygen to be delivered. This means that the body will be put into an increasingly cold state where all cells will slowly die off.

Elsewhere, AE3803 and NT4201 arrive at the lungs where they find a normal cell gasping for air. AE3803 tries to help the cell, only to told by NT4201 that there are more cells begging for oxygen. They drop the oxygen for the cells to use and make their way to get more oxygen. While doing so, NT4201 points out that there are no red blood cells in sight. They return to the lungs to find that the are pumping violently and a large amount of oxygen waiting to be delivered. NT4201 realizes that there aren't enough red blood cells to deliver the oxygen, before AE3803 snaps her back to reality with their task, as everyone is relying on them.

The two deliver oxygen all over the body to the cells to help them survive. As they arrive at the blood vessel wound, Platelet tells the cells not to get blown away. The wind causes many blood cells, including AE3803 and NT4201 to become unnerved. Elsewhere, the tissue cells are in a panic due to the lack of red blood cells. To improve the red blood cells, they decide to increase the blood pressure. However, this backfires as it causes the red blood cells to fall into the wound and increase the hemorrhage. NT4201 is scared but AE3803 tells her to not look behind.

Due to the heavy blood loss from the tissue cells' recklessness, the body temperature decreases even further and they are met with snow. AE3803 and NT4201 bump into a blizzard and try to navigate through it. NT4201 collapses from the frigid cold. AE3803 tries to get NT4201 up, but she refuses, as she believes that the situation is hopeless and the body will die from hemorrhagic shock. AE3803 states that she will continue to the end, as it is their job, so she continues alone despite NT4201's protests. Everyone is attempting to survive, but the blizzard becomes too much for AE3803 and she collapses, lamenting on her uselessness.

AE3803 soon regains consciousness and finds an a red blood cell in front of her, DB5963. AE3803 is shocked to see these red blood cells. The new blood cells are unfamiliar with their surroundings as their uniforms are different to AE3803's. They ask her what she is doing, and she explains the situation to them. DB5963, horrified to learn that the body they are on will die if they do not take action, rallies the group to deliver the oxygen.

The new horde of red blood cells delivers the oxygen everywhere in a pinch, confusing the remaining cells. However, their invaluable assistance stops the hemorrhagic shock and the cells celebrate. AE3803 is tired from the exhausting job and is caught by U-1146, who thanks her for her efforts.

The two look at the scene and wonder where the new red blood cells came from. DB5963 explains that he and his brethren were doing their jobs when a blue tube came out of nowhere and sucked them in, and they did not recall anything afterwards until now. Essentially, someone donated their blood and a successful transfusion was made. He is happy that he is working in a body again. AE3803 decides to search for her kouhai, though NT4201 has already found them. She tells her that she learned that work is not just knowledge, but also requires experience. AE3803 is flustered, but soon finds that NT4201 left and that she is addressing another red blood cell, causing her much embarrassment.

With the hemorrhagic shock over, the cells rebuild their society. AE3803 watches the various cells perform their duties and looks at a map when U-1146 greets her. AE3803 states that she has matured, but U-1146 points out that her map is upside down. U-1146's receptor soon goes off, where a Pseudomonas is being chased by several Neutrophil. U-1146 wishes AE3803 luck as he joins the chase. The normal cell from earlier surprises AE3803, who is patiently waiting for his oxygen delivery.