Planning for Baby's first birthday, the Sinclairs discover evidence that their baby may have been switched with another baby while still an egg. Earl is tantalized by the notion that there is a polite, well-behaved baby out there somewhere who might be his son. Fran is unwilling even to consider the possibility until she meets the other baby – who looks exactly like the Sinclair baby except he is green like Earl – and the other father shares certain personality traits with the Sinclair's baby.