It was a calm day in Cell Village, where the Immune Squad were resting after their last big journey.

But Cell Village was on the brink of disaster! The FLU was planning their invasion. Victor, the FLU leader, and his sidekicks Pinky and Phoebe were about to cause destruction to the body.

Victor is a virus. He and his organization, the FLU, attack the body's cells and cause harm. When your body is infected with a virus, you will sometimes show symptoms like a high fever and pain.

Annie, the antigen receptor, has spotted the virus. She needs to go warn the Immune Squad before they attack!

Annie the antigen receptor can see things that try to hurt the body, like Victor the virus. If an antigen receptor spots a virus, they send out a distress call to warn the other cells of danger.

After she saw Victor the Virus, Annie ran to warn Therell.

"Therell! There is an evil virus that is trying to attack our cell! Activate the other cells!"

Therell is a helper T cell, or a Th cell. Helper T cells release chemicals that activate other parts of the Immune Squad to defend against invaders.

"Baelfire! Theo! There's been an invasion! Activate the immune response!" -said Therell

Theo is a cytotoxic T cell, or a Tc cell. Tc cells attack infected body cells to keep the body healthy.

Baelfire is a B cell. B cells produce antibodies to help the body fight off infection in the future.