Meanwhile, Peter and Chris are playing 'Unga Bunga', a game where one person needs to try to knock their opponent down using mattresses; ignoring Stewie trying to tell them he is watching his program.
Going back three years into the past, he observes the events prior to his conception, like Peter having his own public access show and Lois improvising some lyrics in the theme song in Stewie's place.
Stewie finally succeeds when he gives Peter's porn collection to Goodwill, which Chris found, and writes "Vile Woman" on the wall.
Things seem like fun at first, but Stewie's new older brothers Jaidan and Aidan give him a hard time and turn out to be smarter than his old family.
His new father is a professor at Oxford University and he sets out there to use the lab to build a new time machine to save Peter's and Lois' marriage.
On one hand, it means that 'Chap Stewie' is one of the tightest episodes in recent Family Guy memory, rarely wandering off on tangents and delivering cutaways gags that are linked to the main story.