Peri hears a strange sound and investigates. She finds herself in a room that looks familiar. She sees a box near a window. When she sees what's in the box, she screams.
The Doctor, hearing the scream, runs to the rescue. He finds Peri holding a cooing baby. Peri and the Doctor realise they both see the child and the room differently. Peri sees a brown-haired girl in a room similar to her old room at home. The Doctor sees a blond, curly-haired boy in a room like his kindergarten room.
The Doctor, realising the baby is changing its appearance according to the influence of those around him, and tells Peri that Kamelion is responsible.
Over the next few days, the child grows rapidly. One night it makes its way to the TARDIS console and connects itself to the circuitry. The Doctor catches the child and scolds it for siphoning off the artron energy. This is why the TARDIS has been acting strangely lately.
The Doctor tells Peri that the child, now a teenager, cannot stay on the TARDIS. The teenager wants to leave, and the Doctor realises that these thoughts are reflections of Peri's thoughts, and that she wants to leave.
They drop the "child", now Peri's age, off with Peri's roommate Janine. Peri decides to stay with the Doctor for a few more adventures.
- The TARDIS is saving mementos for the child, including a baseball cap, a champagne cork, some flowers, and a postcard from Seville.
- The Doctor mentions the Pied Piper.
- Peri sees the room decorated with Sesame Street items.
- The Doctor tells the child a fairy tale about the Gastropods.
- Peri's teddy bear, Rhodes, is in her dorm room.
to be added