Sarah helps Caillou paint a birdhouse Dad built, but she can't stay and finish it because she is off on an all-summer trip to China. Caillou and his family take care of Sarah's house and look after Ollie. Caillou misses her very much. On the day of her return, Caillou is ecstatic and anxious to show Sarah that not only is the birdhouse finished and hanging in a tree, it has a resident.