Things will never be the same.......

While the 'growed-ups' at the baby shower talk about the baby that Stu and Didi Pickles are expecting, Tommy Pickles, his friends Chuckie, Phil and Lil, and Angelica go through the baby presents looking for Tommy's new baby sister. After all, Angelica said that babies are "a gift from Bob". But Bob isn't at the party, and neither is Tommy's sister.

The babies have more luck when they go to the 'hopsical' and find it's a baby store. Tommy proudly meets his sister, only to find out that she is a boy named Dil.

Baby Dil is a big pain. He cries all the time and messes up everything. Tommy won't let Phil and Lil take Dil back to the baby store, but before the babies know it, they're on the way to a great adventure in Stu's latest invention: The Reptar Wagon.

While Stu and Didi desperately search for Dil and the babies, Tommy tries to take responsibility for his little brother. But the 'growed-ups' better find the babies soon, because Lil and Phil are about to trade Dil for a baby monkey....