Dean (Jensen Ackles) pressures Sam (Jared Padalecki) into visiting Cicero, Indiana, so he can visit an old flame named Lisa (guest star Cindy Sampson), he had a tryst nine years ago. However, Dean is stunned when he meets not only Lisa again, but also her 8-year old son Ben (guest star Nicholas Elias), who bears a striking resemblance to him.
However, Ben soon goes missing and Sam and Dean discover that a Changeling, a demonic parasite, is snatching kids from the small town and assuming their form. Meanwhile, Ruby (Katie Cassidy) makes contact with Sam and reveals some startling information about his mom.