This first episode sees the return of Tia, Tyler, Theo, Lola and Taylor - now 5 years old - as well as great friends, Alfie and Emily, who are now 6. As before, scientists are on hand to observe their every move. Why is it that siblings are one moment the best of friends and then the worst of enemies? And how will the older brother and sisters respond to meeting up with their old friends.

This second episode sees the return of some of our best loved children but this time we'll see what it's like to be a younger sibling. Charlotte who's 5 years old and 6 year old George are amongst some of the younger children all going on a camping holiday their older brothers and sisters and some new friends. How will they assert their independence with their dominant older siblings around.