The Doctor, Rose and Jack are in Cardiff eating at a diner when the Doctor discovers that the new mayor is none other than one of the Slytheen family.  She is attempting to construct a faulty nuclear facility in Cardiff.  The TARDIS crew, with Mickey's help, capture her and prepare to take her to her home planet once the TARDIS  refuels.  Jack has discovered that she has a sort of cosmic surf board on which she was going to ride the wave of nuclear destruction to outside the solar system.  While they are waiting, the Doctor takes the creature, Bonn, out to eat.  She attempts to get the Doctor to take her elsewhere since she and her whole family have the death sentence on her home planet.  The rift that the TARDIS is using to refuel starts to grown and as they all return to the TARDIS it is discovered that the "surf board" has caused the crack to grow.  Bonn still plans to use it to get away from Earth but the console of the TARDIS opens up and she looks into the heart of the TARDIS.  The energies are held at bay and Bonn reverts to an egg.  The Doctor and companions vow to return the egg to Bonn's home planet so that she can have a new chance at a better life when she grows older.