Janice, a friend and classmate of Charlie Brown and Linus, has not been feeling well lately; she is always tired and has a constant fever, and her bruises are not healing. One day at school, Janice becomes so ill that she has to go home, and her classmates soon find out that she is in the hospital.

After school, Linus and Charlie Brown decide to visit Janice in the hosital, where she tells them that she has leukemia. The news hits Linus especially hard, as he appears to be falling for her. Janice explains what tests the doctors did to discover that she had cancer and explains that some of them did not hurt. She then shows them her IV line and explains her chemotherapy.

After learning of his friend's illness, Linus begins to see life differently, especially when he challenges his sister Lucy's narrow-minded attitude towards Janice's illness ("You could catch leukemia from her and give it to me! ... She probably got the disease because she's a creepy kid."). However, his eyes are really open when Janice comes back. She has lost her hair because of her chemotherapy, and wears a cap to cover her bald head. This attracts the attention of a schoolyard bully, who makes fun of Janice's baldness until an enraged Linus explains that she has cancer and asks if he would like to go through what Janice has gone through