S2·E21 New Kids on the Block
Aired August 30, 2000
Synopsis
An old lot becomes a place of great interest as a house is slowly erected on it. Caillou loves the tractors, diggers and builders. He watches regularly to see the development until one day he discovers that not only is there a new house, but it looks like there might be a new little neighbor. But it turns out there are two! Twins!