Lucy collapses onto the couch in all her outdoor clothes. She's exhausted from running after Little Ricky all day. She describes her day to Ricky when he gets home. He then brings up the topic of sending Little Ricky to nursery school. Lucy is against even reading a selection out of Dr. Spock's book. She finally agrees to enroll Little Ricky in nursery school tomorrow. She cries because she thinks she's "losing her baby."
Fred comes looking for Ethel but learns that she took Little Ricky to the park. But that day the baby was supposed to go to nursery school. Lucy then tells Ricky that she enrolled him just like he told her to do. Ethel comes up, blabbing that Lucy didn't actually take the baby to school. Ricky's upset at Lucy for not taking him and promises that tomorrow he's taking the baby to nursery school.
The next morning Ricky can't find the baby anywhere. Lucy hides him claiming that they are playing hide-and-seek. Fred comes in with the baby hanging off his back. Ricky takes the baby to school.
Lucy tells the Mertzes that Little Ricky didn't even want to come home from school. Everyone's excited about his first painting. But the evening isn't all happy when Lucy gets upset when Little Ricky ends up sick. She blames it on the nursery school. The doctor suggests that when the baby is well again he's going to need to have his tonsils removed.
The Ricardos drop the baby off at the hospital. Lucy tells the nurse that she's going to be right back because she's going to spend the night. The nurse tells her that it's against the rules. Later that night Lucy sneaks out of the apartment to bring the baby his teddy bear. At the hospital she hides it under her coat to look like she's pregnant and waltzes past the nurse's desk. She then hides in the nurses room. Lucy comes out wearing scrubs and places the bear on a stretcher. The stretcher is wheeled into a full operating room. when the head surgeon takes off the sheet he comes face to face with the teddy bear and faints.
Ricky comes to the hospital looking for Lucy. He hears that everyone is looking for a screwball red headed nurse running amok at the hospital. He explains about his wife to the nurse. They go to room 602 where they find Lucy asleep in Little Ricky's bed and tucks them both in for the night.