Robby and Emma are part of Shipwrecked and Single storyline as two of the crew from Queen Solomon cruise ship. They are initially found on the Barren Banks, along with Hugh Bailey, Sandra Barnham and Gina Gibson.
Hugh, Bailey and Sandra are later rescued by a helicopter, but in the end Rob and Emma decided to stay, and can be found in the family bin.
This is one of only two households in the franchise with no "adult" characters (e.g. characters in the young adult, adult, or elder life stages) present. The other is the Newson family from The Sims 2: Apartment Life.