One newcomer red blood cell just wants to do her job. Between bacteria incursions and meeting a certain white blood cell, she's got a lot to learn!

1. Pneumococcus 24m The Red Blood Cell's delivery schedule is interrupted by invading pneumococci bacteria. After a White Blood Cell rescues her, she gets a surprise.

2. Scrape Wound 24m A scrape puts a major dent in the Red Blood Cell's job, but she gets to meet the White Blood Cell again as he fights the invading bacteria and viruses.

3. Influenza 24m The White Blood Cell meets a Naive T Cell who's scared of the invading influenza virus. Luckily the Macrophage and Killer T Cells are there!

4. Food Poisoning 24m When a bacteria appears near the stomach wall, White Blood Cell rushes to the scene. Eosinophil is already there, but she isn't powerful enough.

5. Cedar Pollen Allergy 24m It's cedar pollen season, and allergens are invading. As the Mast Cell produces histamines, the Memory T Cell insists the worst is yet to come.

6. Erythroblasts and Myelocytes 24m Red Blood Cell recalls her past as a young Erythoblast in the red bone marrow. Always getting lost even then, a certain Myelocyte once helped her out.

7. Cancer Cells 24m NK Cell calls a common cell's bluff: turns out he’s Cancer Cell bent on spreading through the body via unchecked cellular proliferation. This means war!

8. The Circulatory System 24m Red Blood Cell wants to make it through the circulatory system all by herself, though she keeps getting lost. White Blood Cell keeps an eye on her.

9. Thymocytes 24m The Helper T Cell and the Killer T Cell seem like polar opposites, but long ago in the thymus, they were both just young T cells with a lot to learn.

10. Staphylococcus aureus 24m After a Monocyte rescues Red Blood Cell from a germ, she heads to the nasal cavity for a warm bath -- just in time for a Staphylococcus Aureus attack!

11. Heatstroke 24m Red Blood Cell heads to the epidermis to cool the body. As heat stroke symptoms worsen, White Blood Cell struggles to fight invading bacillus cereus.

12. Hemorrhagic Shock (Part 1) 24m Red Blood Cell gets her very own rookie to train, but her nerves make her even more inefficient. When a crisis strikes, however, she knows her job.